Language selection

Government of Canada / Gouvernement du Canada

Search

COVID-19 vaccines: Canadian Immunization Guide

For health professionals

Notice

The National Advisory Committee on Immunization (NACI) has provided additional guidance on the available COVID-19 vaccine formulations and products, optimal number of doses of COVID-19 vaccines and other considerations for individuals who have not been previously vaccinated (e.g., by age and for those who are immunocompromised).

This chapter has not yet been updated with the following NACI statement:

Last partial content update: October 20, 2023

This chapter was updated based on the following guidance from the National Advisory Committee on Immunization (NACI):

This information is captured in the table of updates.

On this page

Key information (refer to text and tables for details)

What

Who

How

Why

Back to table of contents at top of page

Epidemiology

Disease description

Infectious agent

COVID-19 is caused by the SARS-CoV-2 virus, which was first recognized in Wuhan, China in December 2019.

Transmission

Current evidence suggests that SARS-CoV-2 is spread through respiratory droplets and aerosols created when an infected person breathes, coughs, sneezes, sings, shouts, or talks. A person may be infectious for up to 3 days before showing symptoms and most people are considered no longer infectious 10 days from onset of symptoms (or first detection of infection if asymptomatic).

More information on the transmission of SARS-CoV-2 can be found on the Public Health Agency of Canada (PHAC) webpages for COVID-19: Main modes of transmission.

Variants of concern

Genetic mutations in the SARS-CoV-2 virus have led to the designation of variants of concern (VOCs). Such mutations may lead to changes in transmissibility, severity of disease or the level of protection offered by vaccines or previous infection.

More information on the VOCs reported in Canada is available in the COVID-19 epidemiology update. The COVID-19 Weekly Epidemiological Update by the World Health Organization (WHO) provides a summary on the global distribution and emerging evidence on VOC and variants of interest (VOI). Differences between VOC and VOI are available from SARS-CoV-2 variants: National definitions, classifications and public health actions.

Risk factors

Anyone can be infected with SARS-CoV-2. However, some populations are at increased risk of exposure to the virus (e.g., due to living or occupational settings), and some populations are at increased risk of severe disease and outcomes (e.g., hospitalization and death) due to biological factors (e.g., advanced age, pre-existing medical conditions, pregnancy) and social factors (e.g., socioeconomic status, belonging to a racialized population) that may intersect. Exposure and risk factors for severe disease may overlap, further increasing risk. Any combination of these factors, as well as varying access to health care services, has the potential for disproportionate consequences for specific populations characterized by increased rates of infection and disease, severe illness, hospitalizations, and/or deaths.

There is a spectrum of COVID-19 disease severity, ranging from asymptomatic to mild, moderate, severe and critical disease. Severe disease more often occurs in those with increasing age and those with underlying medical conditions, with the risk increasing with the number of underlying conditions. A list of underlying medical conditions associated with more severe COVID-19 disease can be found in COVID-19 signs, symptoms and severity of disease: A clinician guide.

There is limited evidence on clinical risk factors for severe COVID-19 disease in pediatric populations. Children at increased risk for severe outcomes may include children who are obese, children who are medically fragile/ have medical complexities, children with more than one comorbidity, children with neurological disorders, and children with immune dysregulation associated with Down syndrome (Trisomy 21) and other immunocompromising conditions.

Spectrum of clinical illness and disease characteristics

The median incubation period (the time from exposure to symptom onset) for non-variant SARS-CoV-2 was estimated to be 4 to 7 days. For Omicron, the median incubation period is 2 to 4 days. The incubation period can range from 2 to 14 days.

Clinical presentation and symptoms of COVID-19 vary in frequency and severity, from asymptomatic to severe and fatal disease. To date, there is no list of symptoms that has been validated to have high specificity or sensitivity for COVID-19.

More information on the spectrum of clinical illness is available on the PHAC webpage for COVID-19 signs, symptoms and severity of disease: A clinician guide.

While most children and adolescents with COVID-19 have mild or no symptoms, some do experience severe disease. However, children and adolescents report fewer severe outcomes of COVID-19 (i.e., hospitalizations due to COVID-19, ICU admission, and deaths) compared to older age groups.

Children, adolescents and adults with SARS-CoV-2 infection are at risk of multisystem inflammatory syndrome (MIS), a rare but serious condition that can occur several weeks following SARS-CoV-2 infection. They are also at risk of post COVID-19 condition (PCC), a condition in which symptoms persist for more than 8 weeks and are present 12 or more weeks following acute infection with SARS-CoV-2. Refer to Effectiveness of vaccination against post-COVID-19 condition.

Disease incidence

Global

Updated international data on COVID-19 cases and deaths are available.

Weekly epidemiological updates highlighting key global, regional and country-level data on COVID-19 cases and deaths are available from WHO.

National

Updated national, provincial and territorial-level data on COVID-19 cases and deaths in Canada over time is available from the PHAC webpage on COVID-19 epidemiology update: Summary.

Back to table of contents at top of page

Preparations authorized for use in Canada

There are some preparations of mRNA COVID-19 vaccines that are no longer available but still authorized for use. These are listed in the chapter Contents of immunizing agents authorized for use in Canada.

mRNA vaccines

COVID-19 vaccines that use mRNA platforms contain mRNA with modified nucleosides that code for the SARS-CoV-2 spike protein. The mRNA can encode for the spike protein from the original SARS-CoV-2 virus or from a variant of concern. A lipid nanoparticle formulation delivers the mRNA into the recipient's cells. Once inside the cytoplasm of a cell, the mRNA provides instructions to the cell's protein production machinery to produce the trans-membrane spike protein antigen that becomes anchored on the cell's external surface. The mRNA does not enter the nucleus of the cell and does not interact with, or alter, human DNA. The immune system is engaged by both the transmembrane spike protein and immune receptors carrying spike antigens to induce humoral and cellular immune responses. The mRNA, lipid nanoparticle, and spike protein are degraded or excreted within days to weeks from time of immunization. mRNA vaccines are not live vaccines and cannot cause infection in the host.

Protein subunit vaccine

Novavax Nuvaxovid consists of a purified full-length SARS-CoV-2 recombinant spike protein nanoparticle co-formulated with the adjuvant Matrix-M. Matrix-M is a novel saponin-based adjuvant that facilitates activation of the cells of the innate immune system, which enhances the magnitude of the spike protein-specific immune response. Matrix-M has been used in Novavax Nuvaxovid clinical trials and in pre-licensure studies for vaccines targeting other pathogens, but has not previously been used in any licensed vaccine.

Virus-like particle (VLP) vaccine

The Medicago Covifenz®COVID-19 vaccine was the first virus-like particle (VLP) COVID-19 vaccine authorized in Canada. Medicago Covifenz was authorized for use in adults 18 to 64 years of age as a primary series but was not marketed.

Viral vector (non-replicating) vaccines

Two viral vector vaccines had been authorized for use in Canada for adults 18 years of age and older; Vaxzevria™ (ChAdOx1-S recombinant) from AstraZeneca Canada (along with the version manufactured by the Serum Institute of India and marketed briefly in Canada as COVISHIELD) and Jcovden COVID-19 vaccine (Ad26.COV2.S) from Janssen Inc. They are no longer available in Canada.

Anti-SARS-CoV-2 monoclonal antibodies authorized for pre-exposure prophylaxis of COVID-19

Tixagevimab and cilgavimab are two recombinant human monoclonal antibodies with amino acid substitutions to extend antibody half-life and thus duration of protection, as well as minimize the potential risk of antibody-dependent enhancement of disease. In addition to authorization for pre-exposure prophylaxis, Evusheld has also been authorized to treat mild to moderate COVID-19.

Up-to-date information on alerts, including risk of treatment failure of specific anti-SARS-CoV-2 monoclonal antibodies as well as safety and recalls, is available from Health Canada. Refer to the product monograph for updates on the neutralization of recent variants and risk of treatment failure.

For complete prescribing information for any of the Preparations authorized for use in Canada, consult the product leaflet or information contained within Health Canada's authorized product monographs available through the Drug Product Database.

Refer to Contents of immunizing agents authorized for use in Canada in Part 1 for lists of vaccines and passive immunizing agents authorized for use in Canada and their contents.

Back to table of contents at top of page

Immunogenicity, efficacy and effectiveness

Immunogenicity

All COVID-19 vaccines induce humoral immune responses, including binding and neutralizing antibody responses, and have been shown to produce cellular immune responses in adult populations. The immune responses may vary depending on the product used, number of doses, interval between the doses (longer intervals result in higher antibody titres), the strains against which the immune response is assessed and how immunologically similar the strain is to the vaccine strain, and the age and underlying medical conditions of the vaccine recipient (antibody titres may be lower in older adults and those who are immunocompromised due to disease or medication). Antibody titres decrease over time since vaccination, although memory responses that can be boosted with vaccination or infection persist.

Antibody titres tend to be higher with vaccines that are antigenically closer to the strain that they are tested against. Clinical studies have shown that bivalent (original plus Omicron BA.4/5 strains) vaccines have lower responses against more recently circulating strains derived from Omicron XBB, than against previously circulating Omicron BA.5. Based on pre-clinical studies, the XBB.1.5 vaccine produces higher antibody titres against strains derived from XBB than the bivalent (original plus Omicron BA.4/5) vaccine.

No immunological correlate of protection has been determined for SARS-CoV-2, and therefore the implications of differences in immune responses post-COVID-19 vaccination on protection against infection and severe disease, as well as on duration of protection, is uncertain.

Efficacy and effectiveness

Efficacy (how well the vaccine works in clinical trials) and effectiveness (how well the vaccine works in real-world observational studies) of COVID-19 vaccines tends to be lowest against infection, somewhat higher against symptomatic disease and highest against severe disease.

Similar to factors that impact the immune response, vaccine effectiveness may be affected by the vaccine product received, the interval between doses (somewhat better with longer intervals), the time since the most recent dose (as immunity wanes), the circulating strains and the age and health status of the recipient and their prior SARS-CoV-2 infection history.

Initial randomized clinical trials using original monovalent vaccines demonstrated high efficacy (over 90%) in adults against symptomatic and severe disease caused by early SARS-CoV-2 strains for both mRNA vaccines (Pfizer-BioNTech Comirnaty and Moderna Spikevax) and the adjuvanted subunit vaccine (Novavax Nuvaxovid).

Studies have also demonstrated efficacy against symptomatic disease of original monovalent vaccines in children, but efficacy was somewhat lower, noting that studies were done later when variants were circulating. Efficacy against severe disease in children 6 months to 4 or 5 years of age could not be assessed because this outcome was rare. Observational studies have also shown protection against hospitalization due to multisystem inflammatory syndrome in children 5 to 18 years of age.

Vaccine protection decreases over time, particularly against infection and symptomatic disease, and to a lesser extent against severe disease as well. Booster doses are intended to increase protection, particularly against severe disease, that may have decreased over time.

Bivalent (original plus Omicron BA.1 or BA.4/5 strain) vaccines enhanced protection against infection/symptomatic disease and severe disease that had waned over time from previous monovalent original vaccines in the context of earlier Omicrons strains such as BA.4/5. The protection offered by bivalent vaccines was similar or somewhat greater than protection offered by original monovalent vaccines against disease due to Omicron. Vaccine effectiveness with the XBB.1.5 formulations in the context of circulating strains will be monitored as usage begins in the fall of 2023 however individuals vaccinated with the updated vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

Protection is higher in those with previous SARS-CoV-2 infection and vaccination (hybrid immunity) than in those who have only been vaccinated or only been infected. A recent Omicron sublineage infection combined with COVID-19 vaccination provides the best protection against future Omicron sublineage infection and severe disease.

Vaccine effectiveness against transmission is also measured in some studies. To the extent that COVID-19 vaccines protect against infection, they also prevent transmission as those who are not infected cannot spread infection to others. In addition, vaccination may offer additional protection against transmission even if infection is not prevented as it may reduce viral load and duration of infection. This has previously been demonstrated particularly with a booster dose, although the duration of this protection against transmission remains uncertain and the impact on transmission against currently circulating strains is unknown.

Effectiveness of vaccination against post-COVID-19 condition

Post COVID-19 condition (PCC) is a condition in which symptoms following a SARS-CoV-2 infection persist for more than 8 weeks and are present for 12 or more weeks following the acute phase. The predominant symptoms experienced with PCC include fatigue, dyspnea, other respiratory issues, cardiovascular issues, pain, sleep disturbances, decrease in quality of life, cognitive impairment, and anxiety or depression. PCC has been estimated to affect approximately 10 to 20% of individuals following COVID-19.

Evidence suggests that receipt of 2 doses of COVID-19 vaccine prior to infection decreases the odds of PCC compared to those who are unvaccinated. There is low confidence that one dose of COVID-19 vaccine prior to infection will decrease the odds of PCC while the impact of a third dose prior to infection is currently uncertain. Whether vaccination following SARS-CoV-2 infection can decrease the risk of PCC remains to be established. Research has not demonstrated a worsening of existing PCC symptoms with vaccination, and appears to be safe. It is unclear if vaccination may change established PCC symptoms.

Back to table of contents at top of page

Recommendations for use

Children

Recommendations for children 6 months to 4 years of age (not moderately to severely immunocompromised)

It is recommended that children 6 months to 4 years of age may be offered a primary series of an mRNA COVID-19 vaccine if they have no contraindications to the vaccine.

For children 6 months to 4 years of age who are not moderately to severely immunocompromised a primary series of Moderna Spikevax (25 mcg) consists of two doses while a primary series of Pfizer-BioNTech Comirnaty (3 mcg) consists of three doses for those 6 months to 4 years of age, using an interval of at least 8 weeks between each dose for both products. There is no preference for the use of Pfizer-BioNTech Comirnaty over Moderna Spikevax COVID-19 vaccines to start or continue the primary vaccine series for this group.

In the coming weeks, NACI will provide additional guidance on the available COVID-19 vaccine formulations and products, optimal number of doses of COVID-19 vaccines and other considerations for individuals who have not been previously vaccinated. This will be particularly relevant for the youngest populations, some of whom may not yet have been exposed to the SARS-CoV-2 virus. Children 6 months to 4 years of age vaccinated with the updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

The current NACI recommendations on vaccine interchangeability applies to XBB.1.5-containing COVID-19 vaccines when used to complete a primary series started with a different formulation (either original monovalent wild type-containing or bivalent vaccine). Regardless of which product was offered to start a primary series, the previous dose should be counted and the series need not be restarted. For mixed schedules consisting of at least one dose of Pfizer-BioNTech Comirnaty (3 mcg), three doses are recommended. Either Pfizer-BioNTech or Moderna Spikevax can be used to complete the remaining doses of the three-dose mixed schedule. Refer to Booster or additional doses for information on additional doses for children 6 months to 4 years of age.

Recommendations for children 6 months to 4 years of age who are moderately to severely immunocompromised

In addition to the above information for children 6 months to 4 years of age who are not immunocompromised, it is recommended that children 6 months to 4 years of age who are moderately to severely immunocompromised and do not have contraindications may be offered a primary series that consists of an extra dose of an mRNA COVID-19 vaccine compared to the age-based schedules noted above for non-immunocompromised children. Therefore, a primary series for children who are moderately to severely immunocompromised consists of three doses of the Moderna Spikevax (25 mcg) vaccine for those 6 months to 4 years of age or four doses of the Pfizer-BioNTech Comirnaty (3 mcg) for those 6 months to 4 years of age, using an interval of 4 to 8 weeks between each dose for both products.

As for non-immunocompromised children, moderately to severely immunocompromised children vaccinated with an updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

Because there are fewer doses in the schedule and thus may be more acceptable and feasible, the Moderna Spikevax (25 mcg) is the recommended product for those who are moderately to severely immunocompromised, however, four doses of the Pfizer-BioNTech Comirnaty (3mcg) vaccine may be offered if the Moderna Spikevax (25 mcg) is not readily available.

For mixed schedules consisting of at least one dose of Pfizer-BioNTech Comirnaty (3 mcg), four doses given 4 to 8 weeks apart are recommended for those who are moderately to severely immunocompromised. Either mRNA product can be used to complete the remaining doses of the four-dose mixed schedule.

Refer to Booster or additional doses for information on additional doses for children 6 months to 4 years of age.

Recommendations for children 5 to 11 years of age (not moderately to severely immunocompromised)

It is recommended that children not moderately to severely immunocompromised and who are 5 to 11 years of age should be offered a primary series of an mRNA COVID-19 vaccine if they have no contraindications to the vaccine.
For children 5 to 11 years of age who are not moderately to severely immunocompromised a primary series of an mRNA vaccine consists of 2 doses, with a dosing interval of at least 8 weeks between the first and second dose.

For these children, there is no preference for the use of Pfizer-BioNTech Comirnaty over Moderna Spikevax COVID-19 vaccines to start or continue the primary vaccine series.

In the coming weeks, NACI will provide additional guidance on the available COVID-19 vaccine formulations and products, optimal number of doses of COVID-19 vaccines and other considerations for individuals who have not been previously vaccinated in various populations.

Children 5 to 11 years of age vaccinated with the updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

The current NACI recommendations on vaccine interchangeability applies XBB.1.5-containing COVID-19 vaccines when used to complete a primary series started with a different formulation (either original monovalent wild type-containing or bivalent vaccine). Regardless of which product was offered to start a primary series, the previous dose should be counted and the series need not be restarted. Children who have received a Pfizer-BioNTech 3 mcg dose starting at 4 years of age and then turn 5 years of age prior to completing their primary series, should be offered three doses in the primary series, however any doses of Pfizer-BioNTech vaccine given at 5 years of age should be 10 mcg. Doses less than 10 mcg at 5 years of age are considered invalid and should be repeated. See PHAC's resource: Quick reference guide on the use of COVID-19 vaccines: Managing vaccine administration errors or deviations for additional guidance.

Refer to Booster or additional doses for information on additional doses for children 5 to 11 years of age.

Recommendations for children 5 to 11 years of age who are moderately to severely immunocompromised

In addition to the above information for those 5 to 11 years of age not moderately to severely immunocompromised, it is recommended that children 5 to 11 years of age who are moderately to severely immunocompromised and do not have contraindications should be offered a primary series of three doses of an mRNA COVID-19 vaccine authorized for their age, using an interval of 4 to 8 weeks between each dose.

Individuals who are moderately to severely immunocompromised may have a decreased response to COVID-19 vaccines and may benefit from a 3-dose primary series with Moderna Spikevax compared to Pfizer-BioNTech Comirnaty. Children 5 to 11 years of age who are moderately to severely immunocompromised vaccinated with the updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

Children who have received Pfizer-BioNTech original or XBB.1.5 (3 mcg) starting at 4 years of age and then turn 5 years of age prior to completing their primary series should be offered four doses in the primary series, however any doses of Pfizer-BioNTech vaccine given at 5 years of age should be 10 mcg. Doses less than 10 mcg at 5 years of age are considered invalid and should be repeated. See PHAC's resource: Quick reference guide on the use of COVID-19 vaccines: Managing vaccine administration errors or deviations for additional guidance.

Refer to Booster or additional doses for information on additional doses for children 5 to 11 years of age.

Adolescents and young adults

Recommendations for adolescents and young adults 12 to 29 years of age (not moderately to severely immunocompromised)

It is recommended that a complete primary series consisting of two doses, preferentially with an mRNA COVID-19 vaccine, should be offered to adolescents and young adults 12 to 29 years of age who are not moderately to severely immunocompromised and do not have contraindications to the vaccine.

In the coming weeks, NACI will provide additional guidance on the available COVID-19 vaccine formulations and products, optimal number of doses of COVID-19 vaccines and other considerations for individuals who have not been previously vaccinated.

In the interim, a primary series with Pfizer-BioNTech Comirnaty (30mcg) is preferred for those 12 to 29 years of age over Moderna Spikevax (50 mcg) due to a lower risk of myocarditis/pericarditis with the Pfizer-BioNTech product in this age group. (Refer to Safety and adverse events, myocarditis or pericarditis following vaccination with an mRNA COVID-19 vaccine).

Individuals vaccinated with the updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

For those who are not moderately to severely immunocompromised, the second dose of the 2-dose primary series of mRNA vaccine should be provided 8 weeks after the first dose.

Eleven year olds who received the 10 mcg Pfizer-BioNTech Comirnaty (or 25 mcg Moderna Spikevax) for their first dose and who have turned 12 years of age by the time the second dose is due should receive 30 mcg of Pfizer-BioNTech Comirnaty to complete their primary series. Moderna Spikevax (50 mcg) can be used for the primary series but Pfizer-BioNTech Comirnaty is preferred for adolescents due to a lower risk of myocarditis/pericarditis. If the second dose of 10 mcg Pfizer-BioNTech Comirnaty is given at 12 years of age, the dose is considered invalid. See PHAC's resource: Quick reference guide on the use of COVID-19 vaccines: Managing vaccine administration errors or deviations for additional guidance. It is recommended that a primary series of an authorized protein subunit COVID-19 vaccine (Novavax Nuvaxovid) should be offered to 12 to 29 year olds without contraindications to the vaccine who are not able or willing to receive an mRNA COVID-19 vaccine. Preference of mRNA vaccines over Novavax Nuvaxovid is due to the availability of more data with regard to the benefits and risks of mRNA vaccines compared to Novavax Nuvaxovid. Both mRNA vaccines and Novavax Nuvaxovid have been associated with a rare risk of myocarditis/pericarditis. An XBB.1.5 formulation of Novavax Nuvaxovid is under review by Health Canada.

Refer to Booster or additional doses for information on additional doses for adolescents and adults.

Recommendations for adolescents and young adults 12 to 29 years of age who are moderately to severely immunocompromised

In addition to the above information for those 12 to 29 years of age who are not moderately to severely immunocompromised, it is recommended that adolescents and young adults who are moderately to severely immunocompromised and without contraindications, be offered a primary series of three doses of an mRNA vaccine with an interval of 4 to 8 weeks between doses.

Individuals vaccinated with an updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

Although Pfizer-BioNTech Comirnaty is preferred over Moderna Spikevax for adolescents and young adults 12 to 29 years of age to reduce the risk of myocarditis/pericarditis, individuals who are moderately to severely immunocompromised may benefit more from a primary series with Moderna Spikevax compared to Pfizer-BioNTech Comirnaty.

The guidance provided above for non-immunocompromised adolescents 11 years of age who turn 12 years of age between their first and second dose also applies to those who are moderately to severely immunocompromised and who turn 12 years of age between their first and second or second and third doses.

Based on clinical discretion, Novavax Nuvaxovid should be offered as a 3-dose primary series to moderately to severely immunocompromised individuals 12 years of age and older who are not able or willing to receive an mRNA COVID-19 vaccine, at a recommended interval of 4 to 8 weeks between doses. An XBB.1.5 formulation of Novavax Nuvaxovid is under regulatory review by Health Canada. It should be noted that the safety and efficacy of Novavax Nuvaxovid has not been established in individuals who are immunocompromised due to disease or treatment. Informed consent for use of either vaccine type in these populations should include discussion that there is currently limited evidence on the use of Novavax Nuvaxovid in these populations, while there is evidence on the safety profile and effectiveness of mRNA COVID-19 vaccines in these populations based on real world use with large numbers of individuals.

Refer to Booster or additional doses for information on additional doses for adolescents and adults who are moderately to severely immunocompromised.

Adults 30 years of age and over

Recommendations for adults 30 years of age and older (not moderately to severely immunocompromised)

It is recommended that a complete primary series of two doses, preferentially with an mRNA COVID-19 vaccine, should be offered to adults 30 years of age and over not moderately or severely immunocompromised and without contraindications to the vaccine.

In the coming weeks, NACI will provide additional guidance on the available COVID-19 vaccine formulations and products, optimal number of doses of COVID-19 vaccines and other considerations for individuals who have not been previously vaccinated.

Individuals vaccinated with the updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

For those who are not moderately to severely immunocompromised, the second dose of the 2-dose primary series of mRNA vaccine should be provided 8 weeks after the first dose.

It is recommended that a primary series of an authorized protein subunit COVID-19 vaccine (Novavax Nuvaxovid) should be offered to individuals 30 years of age and older without contraindications to the vaccine who are not able or willing to receive an mRNA COVID-19 vaccine. Preference of mRNA vaccines over Novavax Nuvaxovid is due to the availability of more data with regard to the benefits and risks of mRNA vaccines compared to Novavax Nuvaxovid. Both mRNA vaccines and Novavax Nuvaxovid have been associated with a rare risk of myocarditis/pericarditis. An XBB.1.5 formulation of Novavax Nuvaxovid is under regulatory review by Health Canada.

Refer to Booster or additional doses for information regarding additional doses for adults.

Recommendations for adults 30 years of age and older who are moderately to severely immunocompromised

In addition to the above information for those 30 years of age and over who are not moderately to severely immunocompromised, it is recommended that adults who are moderately to severely immunocompromised and without contraindications be offered a primary series of three doses, preferentially with an mRNA vaccine, with intervals of 4 to 8 weeks between doses.

Individuals vaccinated with the updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

Individuals who are moderately to severely immunocompromised may have a decreased response to COVID-19 vaccines and may benefit from a 3-dose primary series with Moderna Spikevax compared to Pfizer-BioNTech Comirnaty.

Based on clinical discretion, Novavax Nuvaxovid should be offered as a 3 dose primary series, at a recommended interval of 4 to 8 weeks between doses, to moderately to severely immunocompromised individuals who are not able or willing to receive an mRNA COVID-19 vaccine. The safety and efficacy of Novavax Nuvaxovid has not been established in individuals who are immunocompromised due to disease or treatment. Informed consent for use of either vaccine type in these populations should include discussion that there is currently limited evidence on the use of Novavax Nuvaxovid in immunocompromised populations, while there is evidence on the safety profile and effectiveness of mRNA COVID-19 vaccines in these populations based on real world use with large numbers of individuals.

Refer to Booster or additional doses for information regarding additional doses for adults who are moderately to severely immunocompromised.

Schedule for the primary series

In addition to the information contained in this section, a summary of recommendations, schedules and dosages for most available products can be found on the Public Health Agency of Canada website.

Table 1 provides the immunization schedule and minimum, authorized and optimal interval by product and age for those who are not moderately to severely immunocompromised. Doses administered at less than the minimum interval are considered invalid. See PHAC's resource: Quick reference guide on the use of COVID-19 vaccines: Managing vaccine administration errors or deviations for additional guidance.

For mixed COVID-19 vaccine schedules, the minimum interval between doses should be based on the minimum interval of the product used for the first dose.

Optimal intervals between doses of 8 weeks (or at least 8 weeks) are longer than the authorized intervals as longer intervals are likely to result in a more robust and potentially more durable immune response and potentially higher vaccine effectiveness. Data from adults also suggests an extended interval may be associated with a reduced risk of myocarditis/pericarditis following a second dose of an mRNA COVID-19 vaccine.

For individuals who are moderately to severely immunocompromised, an extra dose is recommended in the primary series and providers should aim to administer each dose of the 3-dose series (or four doses for Pfizer-BioNTech Comirnaty [3 mcg]) 4 to 8 weeks apart from each other. An interval longer than 4 weeks between each dose is likely to result in a more robust and potentially more durable immune response and potentially higher vaccine effectiveness and may be associated with lower risk of myocarditis/pericarditis. However, if a longer interval between doses is being considered, then the need for earlier protection due to risk of exposure (including local transmission of SARS-CoV-2) and risk of severe disease (e.g., underlying high-risk medical condition) should be taken into account. Some moderately to severely immunocompromised individuals may still be susceptible after the first or second doses in the primary series, so their period of susceptibility until receipt of the extra dose will also increase if the interval between doses is increased. Some of these individuals will also remain susceptible after a third dose of COVID-19 vaccine.

Refer to Table 3 for suggested intervals between previous SARS-CoV-2 infection and COVID-19 vaccination.

Note: In the coming weeks, NACI will provide additional guidance on the available COVID-19 vaccine formulations and products, optimal number of doses of COVID-19 vaccines and other considerations for individuals who have not been previously vaccinated. Individuals vaccinated with the updated XBB1.5-containing COVID-19 vaccine are expected to benefit from a greater immune response against currently circulating strains, compared to earlier formulations.

Table 1. Immunization schedule for a primary series, by COVID-19 vaccine for those who are not moderately to severely immunocompromisedFootnote a
Vaccine product (dose) Immunization schedule Authorized age indication Minimum interval Authorized interval Optimal interval Footnote b
Pfizer BioNTech vaccines
Comirnaty Omicron
XBB.1.5 (30 mcg)		 Authorized as one dose; NACI currently recommends 2 doses (under review) 12 years of age and over no data N/A Footnote c 8 weeks
Comirnaty Omicron
XBB.1.5 (10 mcg)		 Authorized as one dose; NACI currently recommends 2 doses (under review) 5 to 11 years of age no data N/AFootnote c 8 weeks
Comirnaty Omicron
XBB.1.5 (3 mcg)		 3-dose schedule 6 months to 4 years of age no data First 2 doses, 21 days apart; 3rd dose at least 8 weeks after 2nd dose 8 weeks between each dose
Comirnaty bivalent BA.4/5 (30 mcg) 2-dose schedule 12 years of age and older no data 21 days 8 weeks
Comirnaty bivalent BA.4/5 (10 mcg, pediatric formulation) 2-dose schedule 5 to 11 years of age no data 21 days 8 weeks
Moderna vaccines
Spikevax XBB.1.5 (50 mcg) Authorized as one dose; NACI currently recommends 2 doses (under review) 12 years of age and over no data 28 days 8 weeks
Spikevax XBB.1.5 (25 mcg) Authorized as 2 doses for 6 months to 4 years and one dose for 5 to 11 years of age; NACI currently recommends 2 doses for all ages (under review) 6 months to 11 years no data 4 weeks for those 6 months to 4 years of age 8 weeks
Spikevax bivalent BA.4/5 (50 mcg) NACI currently recommends 2 doses 12 years of age and older no data N/AFootnote c 8 weeks
Spikevax bivalent BA.4/5 (25 mcg) NACI currently recommends 2 doses 6 to 11 years of age no data N/AFootnote c 8 weeks
Spikevax original (50 mcg) 2-dose schedule 6 to 11 years of age 21 daysFootnote d 28 days At least 8 weeks
Spikevax original (25 mcg) 2-dose schedule 6 months to 5 years of age 28 daysFootnote e 28 days At least 8 weeks
Novavax vaccine
Nuvaxovid 2-dose schedule 12 years of age and older 21 daysFootnote f 21 days 8 weeks
Footnote a

It is recommended that for moderately to severely immunocompromised individuals, an extra dose in addition to those listed above be added to the primary series, with an interval of 4 to 8 weeks between doses. The primary series therefore consists of 3 doses for most individuals who are moderately to severely immunocompromised and 4 doses for Pfizer-BioNTech (3 mcg) for children 6 months to 4 years of age (although this is not the preferred product for this age group).

Return Table 1 to footnote a referrer

Footnote b

There is evidence that longer intervals between the first and second doses of COVID-19 vaccines are likely to result in more robust and potentially more durable immune response and potentially higher vaccine effectiveness and a lower risk of myocarditis/pericarditis. Balancing this potential enhanced protection from a longer interval with simultaneously minimizing the time at risk of infection due to having protection from only 1 dose, for all COVID-19 vaccines in those who are not moderately to severely immunocompromised, an 8-week (or at least 8 week) interval is recommended by NACI.

Return Table 1 to footnote b referrer

Footnote c

N/A means not applicable. This vaccine is not authorized as a 2 dose primary series so there is no authorized interval, however NACI has a recommended 2 dose schedule.

Return Table 1 to footnote c referrer

Footnote d

The basis for this minimum interval is that the majority of participants in the Moderna Spikevax COVID-19 vaccine clinical trials received the second dose 21 to 42 days after the first, as per the pre-defined window.

Return Table 1 to footnote d referrer

Footnote e

The participants in the clinical trial received the second dose a minimum of 28 days after the first dose.

Return Table 1 to footnote e referrer

Footnote f

The basis for this minimum interval is that the majority of participants in the Novavax Nuvaxovid clinical trial received the second dose 21+7 days after the first, as per the pre-defined window.

Return Table 1 to footnote f referrer

Booster or additional doses

All doses of COVID-19 vaccines after the primary series are described as booster doses or additional doses. Note that for moderately to severely immunocompromised individuals, the primary series includes one extra dose that is not referred to as a booster dose.

An mRNA COVID-19 vaccine dose is preferred for the booster or additional dose. Novavax Nuvaxovid should be offered to individuals 18 years of age and older without contraindications to the vaccine who are not able or willing to receive an mRNA COVID-19 vaccine. Preference of mRNA vaccines over Novavax Nuvaxovid is due to the availability of more data with regard to the benefits and risks of mRNA vaccines compared to Novavax Nuvaxovid. Both mRNA vaccines and Novavax Nuvaxovid have been associated with a rare risk of myocarditis/pericarditis.

Beginning in the fall of 2023, those previously vaccinated against COVID-19 are recommended to receive a dose of the XBB.1.5-containing formulation of COVID- 19 vaccine. Immunization is particularly important for those at increased risk of COVID-19 infection or severe disease, for example:

Timing of booster or additional doses

The added protection from a booster or additional dose may be affected by the interval between doses or interval between previous infection and subsequent dose. A longer interval may result in a better response after any subsequent dose, as this allows time for the immune response to mature in breadth and strength and minimizes interference from the response from one dose on the next dose. A longer interval may, however, also increase the chance of a period with waning (lower) protection while awaiting a next dose.

A COVID-19 booster dose may be offered 6 or more months from the last COVID-19 vaccine dose or a known SARS-CoV-2 infection (whichever is later). Booster vaccination using shorter intervals (i.e., 3 months to less than 6 months) following previous vaccination or infection has not been shown to pose a safety risk, though evidence shows that the antibody response is higher with longer intervals between infection and vaccination and with longer intervals between vaccination doses.

Back to table of contents at top of page

Vaccination of specific populations

Pregnancy and breastfeeding

Compared to non-pregnant persons, SARS-CoV-2 infection in pregnancy is associated with increased risk of hospitalization and admission to an intensive care unit (ICU). SARS-CoV-2 infection during pregnancy is also associated with an increased risk in the neonate of preterm birth, low birth weight and admission to a neonatal intensive care unit (NICU).

Recommendations

It is recommended that a complete vaccine series with an mRNA COVID-19 vaccine should be offered to individuals in the authorized age group who are pregnant or breastfeeding (Refer to Recommendations for use section).

Booster recommendations for individuals at increased risk of severe illness from COVID-19 apply to people who are pregnant. An individual may receive all doses for which they are eligible during the course of a pregnancy, regardless of the trimester of pregnancy.

An mRNA vaccine is preferred due to reassuring published data on the safety of these vaccines in pregnancy.

Considerations

Pregnant or breastfeeding individuals were excluded from COVID-19 vaccine clinical trials. However, analysis of data collected through international COVID-19 immunization registries to date have not revealed any maternal or neonatal safety signals.

Informed consent should include discussion that there is real-world evidence on the safety profile and effectiveness of mRNA vaccination with large numbers of individuals who are pregnant or breastfeeding, but currently limited evidence on the use of the Novavax Nuvaxovid vaccine.

Rates of adverse effects are similar in people who are pregnant or breastfeeding and those who are not pregnant or breastfeeding. Studies have not found any impacts of mRNA COVID-19 vaccination on the infant/child being fed human milk or on milk production or excretion. Vaccination during pregnancy does not increase risk for adverse pregnancy/birth outcomes, including miscarriage, stillbirth, low birth weight, preterm birth and NICU admission.

Evidence suggests that COVID-19 mRNA vaccination during pregnancy results in comparable antibody titres to those generated in non-pregnant women. Maternal IgG humoral response to mRNA COVID-19 vaccines transfers across the placenta to the fetus, leading to a significant and potentially protective antibody titre in the neonatal bloodstream 1 week after the second dose. Infants of people who received the second dose of a primary series or a booster dose during pregnancy had a lower risk of hospitalization with COVID-19 (including Omicron) compared to infants born to individuals who were unvaccinated. The effect was greater with the booster dose than the second dose in a primary series and if the dose was given later in the pregnancy as opposed to earlier. The protection from maternal vaccination against infant hospitalization decreases over time since birth. Observational studies consistently show that both anti-spike IgG and IgA are present in breastmilk for at least 6 weeks after maternal vaccination with mRNA vaccines. The protection against disease as a result of breastfeeding is currently unknown.

Individuals who have received a COVID-19 vaccine during pregnancy are encouraged to enroll in a COVID-19 vaccine pregnancy registry (see Table 2).

There is a Canadian COVID-19 Vaccine Registry for Pregnant and Lactating Individuals, hosted at the University of British Columbia and supported by the COVID-19 Immunity Task Force (CITF) to assess the safety and effectiveness of COVID-19 vaccines.

Table 2. Pregnancy registry information by vaccine product
Vaccine product

Registry information

Pfizer-BioNTech Comirnaty COVID-19 vaccine

Pfizer-BioNTech does not have a vaccine registry for pregnant persons. Individuals who are vaccinated with the Pfizer-BioNTech COVID-19 vaccine during pregnancy are encouraged to enroll into the Canadian COVID-19 Vaccine Registry for Pregnant and Lactating Individuals described above.

Moderna Spikevax COVID-19 vaccines

There is a vaccine registry that monitors pregnancy outcomes in persons vaccinated with the Moderna COVID-19 vaccine during pregnancy. Individuals who are vaccinated with the Moderna COVID-19 vaccine during pregnancy are encouraged to enroll in the registry by calling 1-866-MODERNA (1-866-663-3762).

Novavax Nuvaxovid COVID-19 vaccine

There is a vaccine registry that monitors pregnancy outcomes in persons vaccinated with NUVAXOVID during pregnancy. Individuals who are vaccinated with NUVAXOVID during pregnancy are encouraged to enroll in the registry by visiting C-VIPER: COVID-19 Vaccines International Pregnancy Exposure Registry.

Refer to Immunization in pregnancy and breastfeeding in Part 3 for additional general information.

Individuals previously infected with SARS-CoV-2

The immune response due to prior infection may vary due to factors such as the severity of infection, age, presence of comorbidities, the SARS-CoV-2 variant causing the infection, time since the infection and vaccination history. People with both SARS-CoV-2 infection and COVID-19 vaccination are said to have "hybrid immunity" and have the highest vaccine effectiveness against SARS-CoV-2 infection and severe disease compared to either infection or vaccination alone.

Recommendations

COVID-19 vaccines, with a preference for mRNA vaccines, should or may be offered to individuals 6 months of age and older with previous SARS-CoV-2 infection without contraindications to the vaccine based on the recommendation for their age and other risk factors (see Recommendations for use section).

Safety and efficacy data in individuals previously infected with SARS-CoV-2 following vaccination with Novavax Nuvaxovid COVID-19 vaccine are not available.
Refer to Table 3 for suggested intervals between previous infection and COVID-19 vaccination.

Table 3. Suggested intervals between previous SARS-CoV-2 infectionFootnote a and COVID-19 vaccination
SARS-CoV-2 infectionFootnote a timing relative to COVID-19 vaccination Population Suggested interval between SARS-CoV-2 infectionFootnote a and vaccination (clinical discretion is advised)Footnote b Footnote c
Infection prior to completion or initiationFootnote c of primary vaccination series Individuals 6 months of age and older who are not considered moderately to severely immunocompromised and with no history of MIS-C or MIS-A Receive the vaccine 8 weeks after symptom onset or positive test (if asymptomatic)Footnote b
Individuals 6 months of age and older who are moderately to severely immunocompromised and with no history of MIS-C or MIS-A Receive the vaccine dose 4 to 8 weeks after symptom onset or positive test (if asymptomatic)Footnote b
Individuals 6 months of age and older with a history of MIS-C or MIS-A (regardless of immunocompromised status) Receive the vaccine dose when clinical recovery has been achieved or ≥90 days since diagnosis of MIS-C or MIS-A, whichever is longer
Infection after primary seriesFootnote d but before a booster (additional dose) Individuals 6 months of age and older currently eligible for a booster or additional dose

Receive the vaccine dose 6 months after infectionFootnote b

It should be noted that an additional dose using shorter intervals (i.e., 3 months to less than 6 months) following previous vaccination or infection has not been shown to pose a safety risk, though evidence shows that the antibody response is higher with longer intervals between infection and vaccination and with longer intervals between vaccination doses.
Infection following receipt of any additional dose
Footnote a

Previous infection can be defined in different ways based on jurisdictional policies and access to testing. The following suggestion can be considered to define previous infection with SARS-CoV-2:

  • Confirmed by a molecular (e.g., PCR) or Health Canada-approved antigen detection-based test; or
  • Symptomatic disease compatible with COVID-19 AND household exposure to a confirmed COVID-19 case.

Return to footnote a referrer

Footnote b

These suggested intervals are based on immunological principles and expert opinion, and may change as evidence on COVID-19, VOCs, and COVID-19 vaccines emerge. When considering whether or not to administer vaccine doses following the suggested intervals outlined in this table, biological and social risk factors for exposure (e.g., local epidemiology, circulating VOCs, living settings) and severe disease should also be taken into account. These intervals are a guide and clinical discretion is advised.

Return to footnote b referrer

Footnote c

For individuals who have not had any previous doses, they may receive their first dose after acute symptoms of COVID-19 have resolved and they are no longer infectious, or they may follow these suggested intervals. Individual benefit/risk assessment and clinical discretion are advised as per footnote "b". Waiting until at least the infected person is no longer infectious is intended to minimize the risk of transmission of COVID-19 at an immunization venue and to enable monitoring for COVID-19 vaccine adverse events without potential confounding from symptoms of COVID-19.

Return to footnote c referrer

Footnote d

The primary series is outlined in Recommendations for use. Note that for moderately to severely immunocompromised individuals who were immunized with a primary series that includes one extra dose, an additional or booster dose would be subsequent to that dose.

Return to footnote d referrer

Considerations

Testing for previous SARS-CoV-2 infection is not needed prior to COVID-19 vaccination.

A longer interval between infection and vaccination may result in a better immune response from the infection as this allows time for this response to mature in breadth and strength, and for circulating antibodies from the infection to decrease, thus avoiding immune interference when the vaccine is administered.

Current evidence suggests protection is more robust and longer lasting with vaccination in previously infected individuals compared to immunity from SARS-CoV-2 infection alone.

COVID-19 vaccination in individuals previously infected with SARS-CoV-2 has a good safety profile and is well tolerated. Limited evidence suggests reactogenicity may be slightly increased in individuals previously infected with SARS-CoV-2 compared to those with no history of previous infection, however this evidence is limited to the primary series and variants prior to Omicron.

Immunocompromised persons

Recommendations

Those who are moderately to severely immunocompromised should receive an extra dose in the primary series and then subsequent booster doses as recommended following the primary series. Refer to Recommendations for use for specific recommendations based on age for those who are moderately to severely immunocompromised.

Considerations

Immunocompromised individuals, including those receiving immunosuppressive therapy, are at increased risk for prolonged infection and serious complications from SARS-CoV-2 infection. Numerous studies have shown that immunogenicity is substantially decreased in some immunocompromised individuals when compared to healthy vaccine recipients. Observational studies in adults with complete 1 or 2 dose series, show lower vaccine effectiveness against SARS-CoV-2 infection and COVID-19 disease in immunocompromised adults when compared to the general population.

The minimum interval between the initial doses of the primary series and the extra dose should be 28 days but can up to 8 weeks. An interval longer than the minimum 28 days between doses is likely to result in a better immune response. However, moderately to severely immunocompromised individuals (after the initial 1- or 2- doses of the primary series) may still be susceptible during this time before the next dose is administered. If a longer interval between doses is being considered, then the need for earlier protection due to risk of exposure (including local transmission of SARS-CoV-2, circulation of VOC) and risk of severe disease (e.g., underlying high risk medical condition) should be taken into account.

A vaccine series should ideally be completed at least 2 weeks before initiation of immunosuppressive therapies where possible.

Moderately to severely immunocompromised includes individuals with the following conditions:

A range of factors can impact the relative degree of immunocompromise and response to COVID-19 vaccines, and clinical and public health judgement should be applied. Jurisdictions may modify the list based on population considerations.

Refer to Immunization of immunocompromised persons in Part 3 for a suggested definition of high dose steroids and for guidance on vaccination with COVID-19 vaccines for individuals pre- and post-hematopoietic stem cell transplantation (HSCT) and for chimeric antigen receptor (CAR) T cell therapy recipients.

Novavax Nuvaxovid is not currently authorized as a 3-dose primary series and the safety and efficacy of Novavax Nuvaxovid has not been established in individuals who are immunocompromised due to disease or treatment. Based on clinical discretion, Novavax Nuvaxovid should be offered as a 3-dose primary series for moderately to severely immunocompromised individuals in the authorized age group who are not able or willing to receive an mRNA COVID-19 vaccine. Informed consent should include discussion that there is currently limited evidence on the use of Novavax Nuvaxovid in this population, while there is evidence on the safety profile and effectiveness of mRNA COVID-19 vaccines based on real world use with large numbers of individuals.

In observational studies and clinical trials, humoral and cellular immune responses were similar between fully vaccinated people living with HIV on antiretroviral therapy and those who were HIV-negative.

Based on observational studies, the frequency and severity of adverse events following immunization (AEFI) with an mRNA COVID-19 vaccine in certain immunocompromised populations were comparable to those of non-immunosuppressed individuals. No worsening of underlying disease was reported after immunization.

Refer to Immunization of immunocompromised persons in Part 3 for additional general information.

Travellers

Travellers should receive all recommended doses of COVID-19 vaccines, optimally at least 2 weeks before departure. Travellers should verify the travel requirements in place at their destination(s) and for their return to Canada. For more information, refer to the Committee to Advise on Tropical Medicine and Travel (CATMAT) Statement on COVID-19 and International Travel.

Persons new to Canada

Based on a recommendation by PHAC to provinces and territories, people who are planning to live, work or study in Canada who have had only a complete or incomplete primary series of non-Health Canada authorized vaccines, should be offered an additional dose of an mRNA vaccine, unless they have already received 3 doses of a COVID-19 vaccine. They should receive booster doses when eligible.

Back to table of contents at top of page

Serologic testing

Serologic testing is not needed before or after immunization with COVID-19 vaccine.

Back to table of contents at top of page

Administration practices

Dose and route of administration of available products

The text below summarizes all currently available COVID-19 products. In addition, Table 4 summarizes available XBB.1.5 vaccine products.

Dose

Pfizer-BioNTech Comirnaty Omicron XBB.1.5 COVID-19 vaccine

There are several presentations of Pfizer-BioNTech Comirnaty Omicron XBB.1.5 authorized for use. Only the presentations distributed in Canada are listed below.

Pfizer-BioNTech Comirnaty Omicron XBB.1.5 COVID-19 vaccine (30 mcg)

This presentation has a grey cap and a grey label border and is authorized for use in individuals 12 years of age and older.

No dilution is required.

Each dose is 0.3 mL, containing 30 mcg of SARS-CoV-2 XBB.1.5 spike protein mRNA.

Special precaution should be taken to ensure the correct dose is taken from the multi-dose vial.

Pfizer-BioNTech Comirnaty Omicron XBB.1.5 COVID-19 vaccine (10 mcg, pediatric formulation)

This presentation has a blue vial cap and blue label border and is authorized for use in children 5 to 11 years of age.

No dilution is required.

Each dose is 0.3 mL, containing 10 mcg of SARS-CoV-2 XBB.1.5 spike protein mRNA.

Special precaution should be taken to ensure the correct dose is taken from the multi-dose vial.

Pfizer-BioNTech Comirnaty COVID-19 XBB.1.5 vaccine (3 mcg, pediatric formulation)

This presentation has a maroon vial cap and maroon label border and is authorized for use in children 6 months to 4 years of age.

Dilute with 2.2 mL 0.9% Sodium Chloride Injection, USP, prior to use.

Each dose is 0.2 mL after dilution, containing 3 mcg of SARS-CoV-2 XBB.1.5 spike protein mRNA.

Special precaution should be taken to ensure the correct dose is taken from the multi-dose vial.

Pfizer-BioNTech Comirnaty Original and Omicron BA.4/BA.5 COVID-19 vaccine (Bivalent)

There are two presentations of Pfizer-BioNTech Comirnaty bivalent BA.4/5 vaccine authorized for use.

Careful attention should be paid to the vial and carton label, vial cap colour and label border colour when selecting Pfizer-BioNTech Comirnaty COVID-19 vaccine products.

Moderna Spikevax XBB.1.5 COVID-19 vaccine

There is one presentation of Moderna Spikevax XBB.1.5 authorized for use in individuals 6 months of age, supplied as a 0.10 mg/mL suspension in a 2.5 mL multidose vial with a royal blue cap and coral blue label border.

No dilution is required.

The volume required differs by age: 0.25 mL (25 mcg) for 6 months to 11 years and 0.5 mL (50 mcg) for 12 years of age and over.

Moderna Spikevax Bivalent (Original and Omicron BA.4/5) COVID-19 vaccine

There is one presentation of Moderna Spikevax Bivalent BA.4/5 authorized for use as additional or booster doses in individuals 6 years of age and older, supplied as a 0.10 mg/mL suspension in a 2.5 mL multidose vial with a royal blue cap and grey label border. The product can be used off-label as a primary series for those 6 months of age and over.

No dilution is required.

Moderna Spikevax original COVID-19 vaccine

There is one presentation of Moderna Spikevax original authorized for use in individuals 6 months to 11 years of age for the primary series and 6 months of age and over for the booster.

No dilution is required.

The volume (mL) required for primary series differs by age (0.25 mL for 6 months to 5 years and 0.5 mL for 6 to 11 years of age) and for the booster doses (0.25 mL for 6 to 11 years of age and 0.5 mL for 12 years of age and over).

Careful attention should be paid to the vial and carton label, vial cap colour and label border colour when selecting Moderna Spikevax COVID-19 vaccine products.

Novavax Nuvaxovid COVID-19 vaccine

Each dose is 0.5 mL, containing 5 mcg SARS-CoV-2 recombinant original strain spike protein. Vials contain 5 mcg/0.5 mL in a 5.0 mL multidose vial.

The product comes premixed with the Matrix-M adjuvant. No dilution or reconstitution is required.

Table 4. Overview of authorized XBB.1.5 vaccines by product and age
Age group Dose Description Dilution required
Pfizer- BioNTech Comirnaty XBB.1.5
6 months to 4 years 3 mcg (0.2 mL) Cap colour: Maroon;
Label colour: Maroon		 Yes (with 2.2 mL of 0.9% Sodium Chloride)
5 years to 11 years 10 mcg (0.3 mL) Cap colour: Blue;
Label colour: Blue		 No
12 years of age and over 30 mcg (0.3 mL) Cap colour: Grey;
Label colour: Grey		 No
Moderna Spikevax XBB.1.5
6 months to 11 years 25 mcg (0.25 mL) 0.10 mg/mL
Cap colour: Royal blue;
Label colour: Coral blue		 No
12 years of age and over 50 mcg (0.5 mL)

Route of administration

COVID-19 vaccines are given as an intramuscular (IM) injection. The deltoid muscle of the arm is the preferred injection site in adolescents and adults, unless the muscle mass is not adequate or vaccination in that site is not possible, in which case the anterolateral thigh can be used.

Refer to Vaccine administration practices in Part 1 for additional general information, including recommended routes of administration for children.

If an error in vaccine administration occurs, refer to Managing COVID-19 vaccine administration errors or deviations for guidance.

Interchangeability of vaccines

When an XBB.1.5-containing vaccine is used to complete the series started with another COVID-19 vaccine formulation (either original monovalent wild type-containing or bivalent vaccine), the previous dose should be counted and the series need not be restarted.

In the coming weeks, NACI will provide additional guidance on the available COVID-19 vaccine formulations and products for individuals who have not been previously vaccinated.

mRNA COVID-19 vaccines

mRNA vaccines are the preferred products for those who were and were not previously vaccinated.

Novavax Nuvaxovid COVID-19 vaccine

Novavax Nuvaxovid should be used to start or complete a primary series, or used as a booster dose in a mixed prime-boost series, for individuals for whom mRNA COVID-19 vaccine is contraindicated, inaccessible, or has been refused.

Informed consent should include a discussion of the benefits and risks given the limited data available on mixed schedules with Novavax Nuvaxovid. There are currently no data on the use of Novavax Nuvaxovid in a mixed primary series with Moderna Spikevax original (100 mcg) or Janssen Jcovden COVID-19 vaccines. Clinical trial evidence for a heterologous booster dose is available from two randomized controlled trials where adults received a booster dose at least 12 weeks after a primary series with mRNA COVID-19 vaccines or viral vector COVID-19 vaccines. In one, humoral and cellular immune responses against original SARS-CoV-2 were lower compared to after Pfizer-BioNTech Comirnaty original or Moderna Spikevax original. In the other, humoral immune responses were similar to or slightly higher. In both trials, Novavax Nuvaxovid was less reactogenic compared to mRNA COVID-19 vaccines. Evidence on immune responses against recent Omicron sub-lineages is also available from an observational study that showed that a heterologous booster dose of Novavax Nuvaxovid resulted in neutralizing antibody responses against BQ.1.1 and XBB.1 that were slightly lower (but not statistically significant) compared to responses after a bivalent mRNA booster dose.

Mixed COVID-19 vaccine schedules

For mixed COVID-19 vaccine primary series schedules, the minimum interval between doses should be based on the minimum interval of the product used for the first dose. When using mixed schedules, the suggested optimal interval between doses is 8 weeks (or at least 8 weeks) for those who are not moderately to severely immunocompromised. Evidence indicates that mixed COVID-19 viral vector, mRNA and protein subunit vaccine schedules with dosing intervals between 4 and 12 weeks have acceptable safety profiles.

Limited evidence suggests that a mixed schedule in which Novavax Nuvaxovid is administered following a partial or complete primary series of AstraZeneca Vaxzevria or Pfizer-BioNTech Comirnaty original COVID-19 vaccines may not be as immunogenic as continuing with Pfizer-BioNTech Comirnaty original or Moderna Spikevax original vaccines – despite Novavax Nuvaxovid having an acceptable safety profile and immunogenicity.

Concurrent administration with other vaccines

For individuals 6 months of age and older, COVID-19 vaccines may be given concurrently (i.e., same day), or at any time before or after non-COVID-19 vaccines (including live and non-live vaccines).

It is recommended that COVID-19 vaccines may be concurrently administered with other vaccines among all vaccine eligible populations, as there is, to date, no evidence of safety concerns for concurrent administration. In addition, concurrent administration will reduce barriers to the provision of routine childhood immunizations and seasonal influenza immunization. Studies and surveillance activities to assess the safety and immunogenicity of concurrent administration of COVID-19 vaccines with other vaccines are ongoing.

If more than one type of vaccine is administered at a single visit, they should be administered at different injection sites using separate injection equipment. Preferably this is in different limbs, however if the same limb must be used, the injection sites should be separated by at least 2.5 cm (1 inch).

Informed consent should include a discussion of the benefits and risks given the limited data available on administration of COVID-19 vaccines at the same time as, or shortly before or after, other vaccines.

Refer to Timing of vaccine administration in Part 1 for additional general information on concurrent administration of other vaccines.

Pre-vaccination counselling

Prophylactic oral analgesics or antipyretics (e.g., acetaminophen or ibuprofen) should not be routinely used before or at the time of vaccination, but their use is not a contraindication to vaccination. There is currently no evidence of benefit from administration of oral analgesics for the prevention of immunization injection pain or systemic reactions.

Prior to providing a COVID-19 vaccine, informed consent should include discussion about frequently occurring minor adverse events and the risks and symptoms of potential rare severe adverse events.

Anyone receiving any mRNA COVID-19 vaccine should be informed of the risks associated with mRNA COVID-19 vaccines: myocarditis/pericarditis, Bell's palsy and anaphylaxis, and be advised to seek medical attention if they develop signs or symptoms suggestive of these conditions.

Anyone receiving the Novavax Nuvaxovid vaccine should be informed of the risk of myocarditis/pericarditis and anaphylaxis and also be advised to seek medical attention if they develop signs or symptoms suggestive of these conditions.

Refer to Safety and adverse events for further information.

Post-vaccination counselling

Oral analgesics or antipyretics may be considered for the management of adverse events (e.g., pain or fever, respectively), if they occur after vaccination. Analgesics and antipyretics were used in clinical trials of COVID-19 vaccines for the management of pain and/or fever after vaccination.

All vaccine recipients should be instructed to seek medical care if they develop signs or symptoms of a serious adverse event or an allergic reaction following vaccination.

Refer to Vaccine administration practices in Part 1 for additional information on pre- and post-vaccination counseling.

Back to table of contents at top of page

Storage requirements

For information on storage, handling and transport of frozen and thawed vaccine vials, refer to the Overview of key features of COVID-19 vaccines authorized in Canada.

For additional information, consult the product leaflet or information contained within the product monograph available through Health Canada's Drug Product Database. Refer to Storage and handling of immunizing agents in Part 1 for additional general information.

Back to table of contents at top of page

Safety and adverse events

Evidence on vaccine safety is available from COVID-19 clinical trials and ongoing national and international COVID-19 vaccine safety monitoring. The clinical trials solicited adverse events for defined lengths of time following a vaccine dose, as well as collecting unsolicited and serious events.

For reported side effects following COVID-19 vaccination in Canada, refer to the PHAC AEFI report.

Refer to Vaccine safety and pharmacovigilance and Adverse events following immunization (AEFI) in Part 2 for additional information on vaccine safety and for definitions of AEFIs, and reporting of AEFI to public health.

For individuals who develop AEFIs following COVID-19 vaccination, refer to the Contraindications and precautions section for advice on future vaccinations.

Very common and common adverse events

Common adverse events are defined as those that occur in 1% to less than 10% of vaccine recipients; very common adverse events occur in 10% or more of vaccine recipients.

Local

Local adverse events were usually mild or moderate and resolved within a few days of vaccination in all age groups (6 months and older). Pain at the injection site was very common. Redness and swelling were common or very common after administration of any authorized COVID-19 vaccine. Localized axillary (or groin) swelling and tenderness (lymphadenopathy) was a solicited adverse event in the Moderna Spikevax original COVID-19 vaccine clinical trial and was very common after administration of that vaccine.

Systemic

Systemic adverse events were usually mild or moderate and resolved within a few days of vaccination in all age groups (6 months and older). Fatigue, headache, muscle pain, chills, and joint pain were all either common or very common after the administration of any authorized COVID-19 vaccine.

The most frequent reactions reported for children aged 6 months to 2 years included irritability or crying, sleepiness, and loss of appetite. These reactions are common after childhood vaccination.

Adverse events in individuals previously infected with SARS-CoV-2

Limited evidence suggests reactogenicity may be slightly increased in individuals previously infected with SARS-CoV-2 compared to those with no history of previous infection; however, this evidence is limited to the primary series and infection with variants prior to Omicron.

Adverse events following bivalent Omicron- containing mRNA COVID-19 vaccines

Available clinical trial data show that Moderna Spikevax Bivalent BA.1 (50 mcg) and Pfizer-BioNTech Comirnaty Bivalent BA.4/5 (30 mcg) administered as a second booster (second additional) dose to individuals 18 years of age and older and 12 years of age and older, respectively, had similar reactogenicity profiles to that of the respective original versions of each vaccine given as a second booster dose in adults.

For original and Omicron BA.4/5 mRNA bivalent vaccines, post-market safety surveillance data in individuals 12 years of age and older from Canada and the US suggest they are well tolerated with a similar safety profile to the original mRNA COVID-19 vaccines when administered as booster doses.

Uncommon, rare and very rare adverse events

Uncommon adverse events occur in 0.1% to less than 1% of vaccine recipients. Rare and very rare adverse events occur in 0.01% to less than 0.1% and less than 0.01% of vaccine recipients, respectively. The probability of detection of very rare adverse events in clinical trials is low given clinical trial sample sizes; therefore, ongoing pharmacovigilance is essential.

Lymphadenopathy

Lymphadenopathy was an unsolicited event that was uncommonly reported after administration of the Pfizer-BioNTech Comirnaty original (both 10 mcg and 30 mcg formulations) in clinical trials. As noted above, lymphadenopathy was a solicited adverse event in the clinical trials for Moderna Spikevax original and was very commonly reported.

Myocarditis and/or pericarditis following vaccination with mRNA and other COVID-19 vaccines

Rare cases of myocarditis (inflammation of the heart muscle) and/or pericarditis (inflammation of the lining around the heart) have been reported following vaccination with COVID-19 mRNA vaccines.

Cases following mRNA COVID-19 vaccination are consistently reported to have occurred:

Analyses of primary series surveillance data in Canada, US and European Nordic countries suggests a higher rate of myocarditis/pericarditis cases reported after vaccination with Moderna Spikevax original (100 mcg) compared to Pfizer-BioNTech Comirnaty original (30 mcg) vaccine especially among 12 to 29 year old males following a second dose of vaccine.

Myocarditis unrelated to exposure to COVID-19 disease or COVID-19 vaccines is typically less common in younger children 5 to 11 years of age. Safety surveillance data from the US suggests that the risk of myocarditis or pericarditis may be lower in children aged 5 to 11 years following Pfizer-BioNTech Comirnaty original (10 mcg) vaccination compared to adolescents and young adults (who receive a 30 mcg Pfizer-BioNTech original dose). Among children 5 to 11 years of age following vaccination with Pfizer-BioNTech Comirnaty original (10 mcg), very rare cases were most often reported following dose 2 and among males. The risk of myocarditis or pericarditis with Moderna Spikevax original (50 mcg) in children 6 to 11 years of age is unknown. Post-market safety surveillance is ongoing.

Available post-market vaccine safety data from V-safe, Vaccine Safety Datalink (VSD) and Vaccine Adverse Event Reporting System (VAERS) in the US as of September 2022 show that the Moderna Spikevax (25 mcg) and Pfizer-BioNTech Comirnaty (3 mcg) mRNA COVID-19 vaccines are well tolerated among children aged 6 months to 5 years. No safety signals (including myocarditis) have been identified after administration of about 1.5 million vaccine doses.

Evidence from bivalent and original mRNA COVID-19 vaccines across different age groups show that the risk of myocarditis is lower following boosters compared to dose 2 of the primary series, and that no product-specific difference in the risk of myocarditis has been identified following a booster dose at this time. However, while these observations were also seen in adolescents 12 to 17 years of age, the use of Moderna Spikevax COVID-19 vaccines have been limited in those 5 to 17 years of age.

While long-term follow-up is ongoing, available data indicate that the majority of individuals who reported myocarditis/pericarditis after mRNA COVID-19 vaccination, though requiring hospitalization, have responded well to conservative therapy and tend to recover quickly.

Healthcare providers should consider myocarditis/pericarditis in their evaluation if the patient presents with clinically compatible symptoms (e.g., chest pain, shortness of breath, palpitations) after an mRNA COVID-19 vaccine regardless of timing from vaccination to symptoms onset. Investigations include electrocardiogram, serum troponins and echocardiogram. Abnormal electrocardiogram findings and elevated troponin levels have been frequently noted with myocarditis/pericarditis following mRNA vaccine.

Consultation with a cardiologist, infectious disease specialist, or internal medicine specialist may be advisable to assist in this evaluation, particularly to investigate the many potential causes of myocarditis and pericarditis. Investigations may include diagnostic testing for acute COVID-19 infection (e.g., PCR testing), prior SARS-CoV-2 infection and consideration of other potential infectious or non-infectious etiologies including auto-immune conditions.

Cases of myocarditis/pericarditis have been rarely reported following the administration of Novavax Nuvaxovid. Australia's Therapeutic Goods Administration (TGA) reports that as of April 16, 2023, over 251,000 doses of Novavax Nuvaxovid had been administered in the country. Myocarditis was reported in approximately 3 to 4 in every 100,000 people who received a dose of this vaccine. Pericarditis was reported in 13 in every 100,000 people.

A further breakdown of the rates of myocarditis/pericarditis after Novavax Nuvaxovid by age group (including among adolescents), sex and dose number are not available due to the relatively low number of doses given and reported cases. In Europe, over 345,000 doses of Novavax Nuvaxovid have been administered as of December 31, 2022 and myocarditis has been reported at a rate of 20.3 per million doses. In Japan, over 275,000 doses of Novavax Nuvaxovid have been administered as of December 31, 2022, with no reported cases of myocarditis. In Canada, there have been no reported cases of myocarditis or pericarditis following Novavax Nuvaxovid as of March 26, 2023 (following approximately 32,200 doses administered).

Refer to the Contraindications and precautions section for advice on re-vaccination of individuals who developed myocarditis/pericarditis after a COVID-19 vaccine.

Bell's palsy

Very rare cases of Bell's palsy (typically temporary weakness or paralysis on one side of the face) have been reported following vaccination with mRNA COVID-19 vaccines (Pfizer-BioNTech Comirnaty original or Moderna Spikevax original) among individuals aged 12 years and older. Symptoms of Bell's palsy appear suddenly and generally start to improve after a few weeks. The exact cause is unknown. It's believed to be the result of swelling and inflammation of the nerve that controls muscles on the face.

Symptoms of Bell's palsy may include:

Individuals should seek medical attention if they develop symptoms of Bell's palsy following receipt of COVID-19 vaccines. Healthcare providers should consider Bell's palsy in their evaluation if the patient presents with clinically compatible symptoms after a COVID-19 vaccine. Investigations should exclude other potential causes of facial paralysis.

Multisystem inflammatory syndrome in children or in adults (MIS-C or MIS-A) following vaccination with an mRNA COVID-19 vaccine

During the manufacturer-led clinical trials for mRNA COVID-19 vaccines, no cases of MIS-C were reported among children or adolescents. However, any rare or very rare AE that occurs at a frequency less often than 1 in 10,000 would likely not be detected due to the limitations of the trial size.

Very rare cases of MIS-C or MIS-A have been reported following vaccination with COVID-19 mRNA vaccines in Canada and internationally among individuals aged 12 years and older. In October 2021, the European Medicines Agency (EMA) Pharmacovigilance Risk Assessment Committee (EMA-PRAC) issued a statement that there is currently insufficient evidence regarding a possible link between mRNA COVID-19 vaccines and very rare cases of MIS-C or MIS-A.

Severe immediate allergic reactions (e.g., anaphylaxis) following vaccination with COVID-19 vaccines

Anaphylaxis is a very rare, severe, life-threatening allergic reaction typically with a rapid onset that involves multiple organ systems and can progress rapidly. Symptoms and signs of anaphylaxis may include but are not limited to generalized urticaria; wheezing; swelling of the mouth, tongue, and throat; difficulty breathing; vomiting; diarrhea; hypotension; decreased level of consciousness; and shock.

Very rare cases of severe immediate allergic reactions (e.g., anaphylaxis) have been reported following vaccination with mRNA COVID-19 vaccines. Most of the reported cases have occurred within 30 minutes of vaccination.

Individuals tend to recover quickly with appropriate treatment and there have been no fatalities nor long-term morbidity observed with any of these severe immediate allergic reactions in Canada.

Studies have shown that individuals with a severe immediate allergic reaction after a previous dose of mRNA vaccine can be re-vaccinated with the same vaccine or another mRNA COVID-19 vaccine following an appropriate medical assessment. In these studies, re-vaccination was safe and well tolerated with predominantly no, or mild, reactions after re-vaccination when provided in a controlled environment. Available evidence also suggests that most of the reported severe immediate allergic reactions following mRNA COVID-19 vaccines are likely not immunoglobulin E (IgE)-mediated and therefore have a low risk of recurrence following future vaccine doses. Refer to Precautions below for additional information.

Refer to Anaphylaxis and other acute reactions following vaccination in Part 2 for information on the management of anaphylaxis post-vaccination.

Refer to the Contraindications and precautions section for advice on re-vaccination of individuals who had an anaphylactic reaction after vaccination and for vaccination advice for those allergic to components of the COVID-19 vaccines.

Adverse events following vaccination with viral vector vaccines

A number of serious adverse events were observed after the previously available viral vector vaccines Vaxzevria, COVISHIELD and Jcovden (see Preparations authorized for use in Canada).

Venous thromboembolism (VTE) has been observed rarely following vaccination with the Janssen Jcovden COVID-19 Vaccine.

Guillain-Barré syndrome (GBS), a rare but potentially serious immune-mediated neurologic disorder, was identified as having an increased risk following vaccination with the viral vector COVID-19 vaccines (AstraZeneca Vaxzevria and Janssen Jcovden).

Cases of immune thrombocytopenia (ITP) with very low platelet levels (<20,000 per µL) have been reported very rarely after vaccination with Janssen Jcovden and AstraZeneca Vaxzevria COVID-19 vaccines, usually within the first four weeks after vaccination. Very rare cases of capillary leak syndrome (CLS) have been reported following immunization with the viral vector COVID-19 vaccines (AstraZeneca Vaxzevria and Janssen Jcovden). CLS is a very rare, serious condition that causes fluid leakage from small blood vessels (capillaries).

Very rare cases of serious blood clots or thrombosis (at unusual sites such as cerebral venous sinus thrombosis, splanchnic vein thrombosis, as well as arterial thrombosis) associated with thrombocytopenia have been reported following vaccination with viral vector COVID-19 vaccines. These were known as thrombosis with thrombocytopenia syndrome (TTS) along with cases that tested positive for a biomarker, anti-PF4 (antibodies to platelet factor 4-polyanion complexes), representing a subset of events referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT).

The exact mechanism by which the viral vector COVID-19 vaccines trigger this syndrome is still under investigation.

Guidance on reporting adverse events following immunization (AEFI)

Vaccine providers are asked to report AEFIs through local public health departments and to follow AEFI reporting requirements that are specific to their province or territory. In general, any serious (defined as resulting in hospitalization, permanent disability or death) or unexpected adverse event that is temporally related to vaccination should be reported. Refer to Reporting AEFI in Canada for additional information on the completion and submission of AEFI reports.

At the international level, the Brighton Collaboration has developed a list of Adverse Events of Special Interest (AESI). AESI are pre-specified medically significant events that have the potential to be causally associated with a vaccine product. Refer to Brighton Collaboration: COVID-19 resources and tools for the list of AESIs and for case definitions of specific AEFIs.

Refer to Adverse events following immunization (AEFI) in Part 2 for additional information on definitions, reporting, investigating and managing, and causality assessments for AEFIs.

Refer to the PHAC weekly report for reported adverse events following COVID-19 vaccination in Canada.

Contraindications and precautions

Contraindications

Vaccination with a COVID-19 vaccine is contraindicated in individuals who are hypersensitive to the active ingredient or to any ingredient in the formulation, including any non-medicinal ingredient, or component of the container. People with a suspected moderate to severe hypersensitivity reaction, should seek expert advice. Suspected hypersensitivity may not be a reason to not administer vaccine. It should be investigated by an expert to clarify whether the person may proceed with vaccination or not. See the Contraindications and precautions chapter for more information on allergies.

See Precautions section for guidance on possible re-vaccination for individuals with a history of a severe, immediate allergic reaction after previous administration of an mRNA COVID-19 vaccine.

Precautions

Hypersensitivity and allergies

Severe immediate allergic reaction (e.g., anaphylaxis) to an mRNA COVID-19 vaccine

In individuals with a history of a severe, immediate (4 hours or less following vaccination) allergic reaction after previous administration of an mRNA COVID-19 vaccine, re-vaccination may be offered with the same vaccine or the same platform if a risk assessment deems that the benefits outweigh the potential risks for the individual and if informed consent is provided. Consultation with an allergist or other appropriate physician should be sought prior to re-vaccination. If re-vaccinated, vaccine administration should be done in a controlled setting with expertise and equipment to manage anaphylaxis. Individuals should be observed for at least 30 minutes after re-vaccination. For example, a longer period of observation is warranted for individuals exhibiting any symptom suggestive of an evolving AEFI at the end of the 30-minute observation period.

For those with a previous history of allergy to an mRNA vaccine where consultation with an allergist or other appropriate physician precludes further vaccination with an mRNA vaccine, vaccination with Novavax Nuvaxovid should be offered if the individual is in the authorized age group and does not have contraindications to the vaccine. They should also be observed for an extended period of at least 30 minutes after re-vaccination.

Confirmed allergies to a component of a COVID-19 vaccine

Ingredients of authorized COVID-19 vaccines that have been associated with allergic reactions in other products are: polyethylene glycol (PEG), tromethamine (trometamol or Tris) and polysorbate 80. There is a potential of cross-reactive hypersensitivity between PEG and polysorbate.

Table 5. Vaccine products and potential allergens
Vaccine product Polyethylene glycol (PEG) Tromethamine (trometamol or Tris) Polysorbate 80
Pfizer-BioNTech Comirnaty Omicron XBB.1.5 (30 mcg, grey vial cap and grey label border) Yes Yes No
Pfizer-BioNTech Comirnaty Omicron XBB.1.5 (10 mcg, blue vial cap and blue label border) Yes Yes No
Pfizer-BioNTech Comirnaty Omicron XBB.1.5 (3 mcg, maroon vial cap and maroon label border) Yes Yes No
Pfizer-BioNTech Comirnaty Original and Omicron BA.4/5 (bivalent, 30 mcg, 12 years of age and older, grey vial cap and grey label border) Yes Yes No
Pfizer-BioNTech Comirnaty Original and Omicron BA.4/5 (bivalent, 10 mcg, 5 to 11 years of age, orange vial cap and orange label border) Yes Yes No
Moderna Spikevax XBB.1.5 (0.10 mg/mL, royal blue cap and coral blue label border) Yes Yes No
Moderna Spikevax original (0.10 mg/mL, royal blue cap and purple label border) Yes Yes No
Moderna Spikevax Bivalent, Original and Omicron BA.4/5 (0.10 mg/mL, royal blue cap and grey label border) Yes Yes No
Novavax Nuvaxovid No No Yes

In individuals with a confirmed severe, immediate (≤4 hours following exposure) allergy (e.g., anaphylaxis) to a component of a specific COVID-19 vaccine (e.g., PEG), or its container, consultation with an allergist is recommended before receiving the specific COVID-19 vaccine. In individuals with a serious PEG allergy in whom mRNA vaccination is precluded based on a consultation with an allergist or other appropriate physician, vaccination with Novavax Nuvaxovid may be preferred for individuals in the authorized age group without contraindications to Novavax Nuvaxovid. Individuals with a known or suspected serious allergy to a component of a COVID-19 vaccine should be observed for at least 30 minutes after vaccination, if they receive a vaccine containing that component.

It is important to note that other, less serious reactions may mimic allergic reactions (e.g., vasovagal syncope) and vaccination is not contraindicated in these cases.

Mild to moderate immediate allergic reactions to a COVID-19 vaccine or a vaccine excipient

In individuals with mild to moderate immediate allergic reactions (defined as limited in the scope of symptoms and involvement of organ systems or even localized to the site of administration) to a previous dose of mRNA COVID-19 vaccine or any of its components, re-vaccination may be offered with the same vaccine or the same platform (i.e., mRNA). Assessment by a physician or nurse with expertise in immunization may be warranted prior to re-immunization.

Most instances of anaphylaxis to a vaccine begin within 30 minutes after administration of the vaccine. Therefore, if re-vaccination is chosen, an extended period of observation post-vaccination of at least 30 minutes should be provided for the aforementioned individuals.

Other allergies

The following individuals may be routinely vaccinated with COVID-19 vaccines with the following recommended observation periods.

30 minute post-vaccination observation period:

15 minute post-vaccination observation period:

Acute illness

Vaccination of individuals who may be currently infected with SARS-CoV-2 is not known to have a detrimental effect on the illness. However, vaccination should be deferred in individuals with confirmed or suspected SARS-CoV-2 infection, or those with respiratory symptoms, to minimize the risk of COVID-19 transmission at an immunization clinic/venue. If any person is identified with symptoms on arrival at the venue, they should not be immunized and should be instructed to seek medical and public health advice as appropriate and follow current local public health measures.

The recommended intervals between SARS-CoV-2 infection and COVID-19 vaccination are provided in Table 3.

Bleeding disorders

In individuals with bleeding disorders, the condition should be managed prior to immunization to minimize the risk of bleeding. Individuals receiving long-term anticoagulation are not considered to be at higher risk of bleeding complications following immunization and may be safely immunized without discontinuation of their anticoagulation therapy.

Myocarditis and/or pericarditis following vaccination

As a precautionary measure until more information is available, further doses of mRNA COVID-19 vaccines should be deferred among individuals who have experienced myocarditis and/or pericarditis within 6 weeks following a previous dose of an mRNA COVID-19 vaccine in most circumstances. This includes any person who had an abnormal cardiac investigation including ECG, elevated troponins, echocardiogram or cardiac MRI after a dose of an mRNA COVID-19 vaccine.

Those with a history compatible with pericarditis and who either had no cardiac workup or had normal cardiac investigations, can receive the next dose once they are symptom-free and at least 90 days have elapsed since vaccination.

Some individuals 5 years of age and older with confirmed myocarditis and/or pericarditis after a dose of an mRNA COVID-19 vaccine may choose to receive another dose of vaccine after discussing the risk and benefit with their healthcare provider. If another dose of vaccine is offered, it should be with a Pfizer-BioNTech Comirnaty COVID-19 vaccine product (original for the primary series or bivalent for the booster dose, at the age-appropriate dose) due to the lower reported rate of myocarditis and/or pericarditis following the Pfizer-BioNTech Comirnaty original (30 mcg) vaccine compared to the Moderna Spikevax original (100 mcg) vaccine among individuals 12 years of age and older. Informed consent should include discussion about the unknown risk of recurrence of myocarditis and/or pericarditis following receipt of additional doses of Pfizer-BioNTech Comirnaty original or bivalent vaccines in individuals with a history of confirmed myocarditis and/or pericarditis after a previous dose of mRNA COVID-19 vaccine, as well as the need to seek immediate medical assessment and care should symptoms develop.

There have been case reports of myocarditis and/or pericarditis following the administration of Novavax Nuvaxovid. Data from the clinical trials and global safety surveillance have suggested an increased risk.

Individuals who have a history of myocarditis unrelated to mRNA or protein subunit COVID-19 vaccination should consult their clinical team for individual considerations and recommendations. If the diagnosis is remote and they are no longer followed clinically for cardiac issues, they should receive the vaccine.

Guillain-Barré syndrome

Individuals with past history of GBS unrelated to COVID-19 vaccination should receive an mRNA COVID-19 vaccine. When mRNA COVID-19 vaccines are contraindicated, Novavax Nuvaxovid should be considered or individuals may receive a viral vector COVID-19 vaccine after weighing the risks and benefits in consultation with their health care provider.

Individuals who developed GBS after a previous dose of a COVID-19 vaccine may receive an mRNA COVID-19 vaccine, after consultation with their health care provider if it is determined that the benefits outweigh the risk and informed consent is provided.

Bell's palsy

Individuals should seek medical attention if they develop symptoms compatible with Bell's palsy following receipt of mRNA COVID-19 vaccines. Healthcare providers should consider Bell's palsy in their evaluation if the patient presents with clinically compatible symptoms after an mRNA COVID-19 vaccine. Investigations should exclude other potential causes of facial paralysis.

Multisystem inflammatory syndrome in children or adults (MIS-C or MIS-A)

For children or adults with a previous history of MIS-C or MIS-A, vaccination or re-vaccination should be postponed until clinical recovery has been achieved or until it has been ≥ 90 days since diagnosis, whichever is longer (see Table 3).

Back to table of contents at top of page

Other considerations

Tuberculin skin testing (TST) or interferon gamma release assay (IGRA)

There is a theoretical risk that mRNA or viral vector vaccines could temporarily affect cell-mediated immunity, resulting in false-negative TST or IGRA test results. However, there is no direct evidence for this interaction. Therefore, in the absence of data and acknowledging the importance of both timely tuberculosis testing and immunization, vaccination with COVID-19 vaccines may take place at any time before, after or at the same visit as the TST or IGRA test. Repeat tuberculin skin testing or IGRA (at least 4 weeks post-COVID-19 immunization) of individuals with negative TST or IGRA results for whom there is high suspicion of latent tuberculosis infection may be considered in order to avoid missing persons with TB infection.

Blood products, human immunoglobulin and timing of immunization

It is recommended that COVID-19 vaccines should not be given concurrently with anti-SARS-CoV-2 monoclonal antibodies.

Administration of these products concurrently may result in decreased effectiveness of the COVID-19 vaccine and/or anti-SARS-CoV-2 monoclonal antibodies. Anti-SARS-CoV-2 monoclonal antibodies have high affinity for the spike protein expressed by COVID-19 vaccines, which could prevent the production of antibodies stimulated by the vaccine, or binding of vaccine antigen to the monoclonal antibody may neutralize the monoclonal antibody.

Pre-exposure prophylaxis for COVID-19 with anti-SARS-CoV-2 monoclonal antibodies

In some cases, anti-SARS-CoV-2 monoclonal antibodies may be given in addition to vaccination to some individuals with immunocompromising conditions, in consultation with clinical experts. Clinicians may consider the following factors when assessing the potential benefits or risks when recommending anti-SARS-CoV-2 monoclonal antibodies to their patients: the degree of immunocompromise, the presence of additional risk factors for severe COVID-19, the likelihood of not responding to COVID-19 vaccine, the risk of exposure to COVID-19 due to occupational or residential circumstances, as well as local circulation of variants with the potential for resistance to one or more of the anti-SARS-CoV-2 monoclonal antibodies, including some Omicron sublineages. Although anti-SARS-CoV-2 monoclonal antibodies could reduce humoral immune responses to a COVID-19 vaccine, cellular immune responses may not be impacted. Cellular immune responses to a COVID-19 vaccine are important for immunocompromised populations and, to sustain cellular immune responses, vaccination should be given to this group as recommended, whether or not their receive anti-SARS-CoV-2 monoclonal antibodies, noting the timing considerations below.

Implementation advice to inform decision-makers on the appropriate use of anti-SARS-CoV-2 monoclonal antibodies (e.g., patient prioritization) is available from the Canadian Agency for Drugs and Technologies in Health (CADTH), the Institut national d'excellence en santé et en services sociaux (INESSS) and Ontario Health (PDF).

Up-to-date information on alerts including risk of treatment failure of specific anti-SARS-CoV-2 monoclonal antibodies as well as safety and recalls, is available from Health Canada.

Guidance on anti-SARS-CoV-2 monoclonal antibodies may change as additional evidence emerges.

Administration of anti-SARS-CoV-2 monoclonal antibodies following COVID-19 vaccines

To minimize interference, it is recommended that anti-SARS-CoV-2 monoclonal antibodies should be administered at least 2 weeks following COVID-19 vaccination.

Administration of COVID-19 vaccines following anti-SARS-CoV-2 monoclonal antibodies

There is no evidence on which to base a specific minimum interval for COVID-19 vaccination following anti-SARS-CoV-2 monoclonal antibodies administration. Timing should be assessed in consultation with clinical experts on a case-by-case basis.

Therapeutic management of COVID-19 with anti-SARS-CoV-2 monoclonal antibodies

Multiple products are authorized in Canada for therapeutic management of COVID-19. Expert clinical opinion should be sought on a case-by-case basis when deciding on the use of anti-SARS-CoV-2 monoclonal antibodies, as well as whether vaccination should be repeated if a therapeutic dose is given too close to vaccination.

Timing of administration of COVID-19 vaccines following administration of therapeutic anti-SARS-CoV-2 monoclonal antibodies should be assessed in consultation with clinical experts on a case-by-case basis.

For complete prescribing information, consult the product leaflet or information contained within the product monograph available through Health Canada's Drug Product Database.

Back to table of contents at top of page

Chapter revision process

This chapter was updated to reflect guidance based on current evidence and the National Advisory Committee on Immunization's (NACI's) expert opinion since the last version of this chapter (June 27, 2023). Additional content changes may reflect changes to COVID-19 vaccine product monographs. Refer to the Table of updates for additional information.

For supporting information on COVID-19 vaccine chapter updates, including additional references, refer to the current and/or previous summary of updates in the Canadian Immunization Guide published on the NACI webpage under COVID-19.

Back to table of contents at top of page

Acknowledgements

This chapter was prepared by C Jensen, R Pless, B Warshawsky, R Krishnan, E Wong, J Zafack, MI Salvadori, N Forbes, E Abrams, K Young, MC Tunis, S Wilson, R Harrison, and S Deeks on behalf of NACI.

NACI gratefully acknowledges the contribution of: N Haddad.

Back to table of contents at top of page

Selected references

Back to table of contents at top of page

Page details

Date modified: