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Planning guidance for immunization clinics for COVID-19 vaccines: Managing vaccine administration errors or deviations

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Preamble

This guidance document is for health care providers. It offers an approach to managing COVID-19 vaccines that are administered in a manner that differs from the recommendations of the manufacturer as authorized by Health Canada and/or the National Advisory Committee on Immunization (NACI). These are referred to as vaccine administration errors or deviations. This document builds on guidance developed by:

We also received input from the Canadian Immunization Committee and NACI.

For complete NACI advice, please see the following:

There is limited evidence to guide the management of these situations. This document provides guidance only. Note that provincial and territorial protocols may differ from this guidance document. Clinical judgment is necessary for making appropriate decisions regarding vaccine administration errors and deviations and may result in management decisions that differ from those outlined in this guidance.

Note that this document should be used only to manage errors or deviations that have already occurred. In order to prevent errors or deviations from occurring, please follow provincial/territorial guidance, the product monographs and recommendations from NACI statements and publications when administering COVID-19 vaccines. Training, educational resources, policies and procedures and oversight are useful tools to support the prevention of errors and deviations.

The term "valid" in this document refers to a dose that is considered acceptable for the purposes of managing an error or deviation and not for the proof of vaccination requirements.

What to do after an error or deviation is detected

If an inadvertent vaccine administration error or deviation is found, health care providers should:

As with usual practice, when managing errors and deviations, inquire about the client's history of adverse events following vaccination. If they experienced a significant local or systemic reaction, base your decision to offer subsequent doses on a case-by-case basis in consultation with an allergist, immunologist or another appropriate physician.

If the client who had a repeat dose following an invalid dose requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and at the suggested optimal interval. Count the interval from the repeat dose.

Refer to the Canadian Immunization Guide COVID-19 vaccines chapter for tables containing the schedule for a primary series or the schedule for a primary series for individuals who are moderately to severely immunocompromised as well as information on booster doses.

Serologic testing to assess vaccine-induced immunity following COVID-19 vaccine errors or deviations is generally not recommended. Health care providers are encouraged to contact their local public health authority and/or their provincial or territorial public health laboratory for advice if considering using serology to investigate an error or deviation.

For other resources on vaccine administration practices, please consult the Canadian Immunization Guide.

Type of administration errors or deviations: Guiding principles, recommended actions, and examples

Site or route errors

Guiding principles for site or route errors

COVID-19 vaccines should be administered intramuscularly. The anterolateral thigh (vastus lateralis) is the preferred site for children less than 1 years of age. The anterolateral thigh or the deltoid muscle can be used for toddlers and older children. The deltoid is usually selected as the injection site in these age groups as temporary muscle pain post-vaccination in the anterolateral thigh muscle may affect ambulation. The deltoid muscle of the arm is the preferred injection site in adolescents and adults (unless the muscle mass is not adequate, in which case the anterolateral thigh can be used) [Route, site and technique for vaccine administration: Canadian Immunization Guide].

The dose of COVID-19 vaccine varies by product and/or age. See the Recommendations for use in the Canadian Immunization Guide: COVID-19 vaccine chapter.

Examples

Incorrect site

If a site other than the deltoid muscle or anterolateral thigh is used:

  • consider the dose valid
  • inform the client (and parent or guardian) of the error or deviation and the potential for local and systemic adverse events and that the dose is acceptable
Incorrect route

If an incorrect route (for example, subcutaneous) is used:

  • consider the dose valid
  • inform the client (and parent or guardian) of the error or deviation and the potential for local and systemic adverse events and that the dose is acceptable

Too high a dose, or an unknown dose that is likely to be lower than the authorized dose

Guiding principle for too high a dose

Doses that are higher than the authorized amount are considered valid. The client should be advised of the potential for local and systemic adverse events.

Guiding principle for an unknown dose that is likely to be lower than the authorized dose (for example, leaked out, equipment failure, client pulled away)

Doses that are lower than the authorized amount may result in a sub-optimal response and may need to be repeated.

Note that for doses that are known and are lower than the authorized dose, see section on dose, product or schedule error based on age.

Examples

For all ages, if a higher than authorized dose is administered
  • Consider the dose valid.
  • Inform the client of the potential for local and systemic adverse events.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dose, product and follow the suggested optimal interval.
For all ages, if a lower but unknown dose was administered (for example, leaked out, equipment failure, client pulled away)
  • If less than a full dose was administered or the proportion of the dose administered cannot be estimated, consider the dose invalid.
  • Offer a full repeat dose as soon as the error is recognized.
  • If this is the same day as the invalid dose, use a separate anatomic injection site whenever possible (e.g., different limb).
  • Inform the client of the potential for local and systemic adverse events with the full repeat dose.
  • If the client requires a subsequent dose in the primary series, give it with a recommended age-appropriate dose, product and follow the suggested optimal interval from the full repeat dose.

Mixed schedules

Guiding principle for mixed schedules for all ages

If a different COVID-19 vaccine was used for the first, second or additional or booster doses, consider all doses valid (assuming the age-appropriate dose was used for each product).

Guiding principles for children 6 months to 4 years of age

NACI has recommended that for children 6 months to 4 years of age, if readily available (i.e., easily available at the time of vaccination without delay or vaccine wastage), the same mRNA COVID-19 vaccine product should be offered for (the) subsequent dose(s) in a vaccine series started with a specific mRNA COVID-19 vaccine (Recommendations on the use of Pfizer-BioNTech Comirnaty [3 mcg] COVID-19 vaccine in children 6 months to 4 years of age).

If 2 different products are used in the same primary series (i.e., a mixed schedule), the Public Health Agency of Canada (PHAC) is recommending that the number of doses should be as per the Pfizer-BioNTech Comirnaty schedule (i.e., 3 doses for non-immunocompromised individuals with at least an 8 week interval between doses, and 4 doses for those who are moderately to severely immunocompromised with a 4 to 8 week interval between doses) [PHAC recommendation]. This recommendation is provided because the Pfizer-BioNTech Comirnaty mRNA content is lower than the Moderna Spikevax mRNA content. Therefore, to support an optimal response, the Pfizer-BioNTech Comirnaty schedule is used if any of the doses in a mixed schedule were Pfizer-BioNTech Comirnaty because it consists of more doses than the Moderna Spikevax schedule.

Either age-appropriate mRNA vaccine can be used to complete the primary series of a mixed schedule.

Note that NACI has recommended that for those 6 months to 4 years of age who are moderately to severely immunocompromised, a primary series of Moderna Spikevax vaccine (25 mcg) is preferred because it only requires 3 doses (Recommendations on the use of Pfizer-BioNTech Comirnaty [3 mcg] COVID-19 vaccine in children 6 months to 4 years of age). However, as 4 doses are recommended in a mixed schedule with Pfizer-BioNTech Comirnaty for those who are moderately to severely immunocompromised, either product can be used to complete the primary series.

For mixed schedules involving the transition from 4 to 5 years of age, see guiding principles for children 6 months to 11 years of age in the dose, product or schedule error based on age section.

Examples

Product administered as a first dose of the primary series to an individual 6 months to 4 years of age who is immunocompetent was a 25 mcg dose of Moderna Spikevax and the second dose administered was a 3 mcg dose of Pfizer-BioNTech Comirnaty or vice versa
  • Consider the primary series not complete.
  • Offer a third dose of either mRNA vaccine at least 8 weeks after the second dose to complete the 3-dose primary series.
Product administered to an individual 6 months to 4 years of age who is moderately to severely immunocompromised included 3 doses, of which at least 1 dose was Pfizer-BioNTech Comirnaty and at least 1 dose was Moderna Spikevax
  • Consider the primary series not complete.
  • Offer a fourth dose of either mRNA vaccine, 4 to 8 weeks after the third dose to complete the 4-dose primary series.

Dose, product or schedule error based on age

Select the age group of your client:

Children 6 months to 11 years of age

Guiding principles for children 6 months to 11 years of age

Primary series age transitions

If while receiving their primary series, a child transitions from 4 to 5 years of age for Pfizer-BioNTech Comirnaty or 5 to 6 years of age for Moderna Spikevax, NACI recommends that they should receive the appropriate dose for their current age and follow the primary series product schedule based on the age that they started the series (Recommendations on the use of Pfizer-BioNTech Comirnaty [3 mcg] COVID-19 vaccine in children 6 months to 4 years of age).

  • For Pfizer-BioNTech Comirnaty, they should receive 3 mcg when they are 4 years of age and 10 mcg when they are 5 years of age. They should receive 3 doses in the primary series (as recommended for children 6 months to 4 years of age) if they are immunocompetent and 4 doses in the primary series if they are moderately to severely immunocompromised.
  • For Moderna Spikevax, they should receive 25 mcg when they are 5 years of age and 50 mcg when they are 6 years of age. They should receive 2 doses in the primary series if they are immunocompetent and 3 doses in the primary series if they are moderately to severely immunocompromised.
  • Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 6 to 11 year olds due to a lower risk of myocarditis/pericarditis.
  • For mixed schedules:
    • If the first dose is 3 mcg of Pfizer-BioNTech Comirnaty at 4 years of age and the second dose is 25 mcg Moderna Spikevax at 5 years of age, they should receive 3 doses in the primary series (as recommended for children 6 months to 4 years of age based on the Pfizer-BioNTech Comirnaty schedule) if they are immunocompetent and 4 doses in the primary series if they are moderately to severely immunocompromised. Either age-appropriate mRNA vaccine can be used to complete the primary series of a mixed schedule using the age-appropriate dose for their current age.
    • If the first dose is 25 mcg of Moderna Spikevax at 4 or 5 years of age and the second dose is 10 mcg of Pfizer-BioNTech Comirnaty at 5 or 6 years of age, the primary series is complete for those who are immunocompetent. An additional dose is needed if they are moderately to severely immunocompromised. Either age-appropriate mRNA vaccine can be used to complete the primary series of a mixed schedule for those who are moderately to severely immunocompromised using the age-appropriate dose for their current age.
Booster doses

Boosters are only authorized for those 5 years of age and over. The booster dose recommendations are based on the child's age at the time of the booster and not their age at initiation of the primary series (e.g., children who were 4 years of age when they started their primary series and are now 5 years of age and are 6 months following the primary series of an mRNA vaccine should receive a Pfizer-BioNTech Comirnaty booster if they have an underlying medical condition that puts them at high risk for severe illness due to COVID-19 and may receive a booster if they do not [as per NACI Pfizer-BioNTech Comirnaty booster dose recommendations]).

Only the Pfizer-BioNTech Comirnaty monovalent original product is authorized as a booster for children 5 to 11 years of age, however if Pfizer-BioNTech Comirnaty bivalent Omicron-containing vaccine or Moderna Spikevax vaccine (monovalent original or bivalent) is administered to this age group as a booster, they should be considered valid, assuming a valid dosage amount was administered.

The dose is known to be too low

For Pfizer-BioNTech Comirnaty, in children 6 months to less than 5 years of age, the age-appropriate dose is 3 mcg. Any dose less than 3 mcg is considered invalid (PHAC recommendation). This recommendation is provided because any dose less than 3 mcg may not result in an optimal response. Note that if more than 1 dose in the primary series was discovered to be invalid, clinical judgment will be required about whether to repeat earlier doses.

For Moderna Spikevax, the age-appropriate dose for children 6 months to less than 6 years of age is 25 mcg. Any dose less than 25 mcg is considered invalid (PHAC recommendation). This PHAC recommendation is provided because any dose less than 25 mcg may not result in an optimal response. Note that if more than 1 dose in the primary series was discovered to be invalid, clinical judgment will be required about whether to repeat earlier doses.

For Pfizer-BioNTech Comirnaty, in children 5 to 11 years of age, the age-appropriate dose is 10 mcg. Any dose less than 10 mcg is considered invalid (PHAC recommendation). This recommendation is provided because any dose less than 10 mcg may not result in an optimal response. Note that if more than 1 dose in the primary series was discovered to be invalid, clinical judgment will be required about whether to repeat earlier doses.

For Moderna Spikevax, the age-appropriate dose for children 6 to 11 years of age is 50 mcg. For error management, a 25 mcg dose is considered valid for a 6 year old who started the series at 5 years of age (NACI recommendation). For children starting the series at 6 years of age and for children 7 to 11 years of age, a dose less than 50 mcg is considered invalid (PHAC recommendation). This PHAC recommendation is provided because the dose less than 50 mcg may not result in an optimal response. Note that if more than 1 dose in the primary series was discovered to be invalid, clinical judgment will be required about whether to repeat earlier doses. Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 6 to 11 year olds due to a lower risk of myocarditis/pericarditis.

If the error resulting in an invalid dose is discovered in time, a repeat dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb). See examples for possible dosages to use for the repeat dose.

  • If the repeat dose cannot be given on the same clinic day:
    • If Pfizer-BioNTech Comirnaty is the invalid dose and it is the first dose in the primary series, repeat immediately once recognized with a full age-appropriate dose. If Pfizer-BioNTech Comirnaty is the invalid dose and it is the second dose (or third dose for those who are moderately to severely immunocompromised), repeat 21 days (manufacturer's authorized interval) after the invalid dose using a full age-appropriate dose. This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events.
    • If Moderna Spikevax is the invalid dose and it is any dose in the primary series, repeat 28 days (manufacturer's authorized interval) after the invalid dose using a full age-appropriate dose. This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events.
    • If the invalid dose is a booster dose, repeat 8 weeks after the invalid dose using a full age-appropriate dose. The waiting period is intended to avoid interference with the response that may develop to the invalid booster dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the child requires a subsequent dose in the primary series or a booster dose, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose.

Examples

Product administered to a child 5 to 11 years of age was a 3 mcg dose of Pfizer-BioNTech Comirnaty (lower than authorized dose) as part of a primary series, or as a booster dose
  • Consider the dose invalid.
  • Note if more than 1 dose in the primary series was given as 3 mcg to a child 5 to 11 years of age, the latest dose should be considered invalid, and clinical judgment is required to determine if the earlier doses should be accepted or considered invalid.
  • If the error is discovered in time, a full repeat age-appropriate dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the repeat dose cannot be given on the same clinic day:
    • If the 3 mcg dose is the first dose in the primary series, offer a full age-appropriate dose immediately.
    • If the child is immunocompetent and the 3 mcg dose is the second dose, offer a full age-appropriate dose 21 days (manufacturer's authorized interval) after the invalid dose.
    • If the child is moderately to severely immunocompromised and the 3 mcg dose is the second or third dose, offer a full age-appropriate dose 21 days (manufacturer's authorized interval) following the invalid dose.
    • If the 3 mcg dose is a booster dose, wait 8 weeks to offer a full age-appropriate dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the child requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
Product administered for the first dose of the primary series to a child 4 years of age was a 3 mcg dose of Pfizer-BioNTech Comirnaty and the child, now 5 years of age, received 3 mcg of Pfizer-BioNTech Comirnaty for dose 2
  • Consider the second dose invalid.
  • If the error is discovered in time, a full repeat age-appropriate dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the repeat dose cannot be given on the same clinic day:
    • If the child is immunocompetent, offer a full age-appropriate dose 21 days (manufacturer's authorized interval) after the invalid dose. Because the series was started at 4 years of age with Pfizer-BioNTech Comirnaty, the child requires 3 doses in the primary series. Offer the third valid dose at least 8 weeks from the repeat dose. A booster dose 6 months from the third dose should or may be offered as per NACI recommendations, depending on if the child has underlying medical conditions that put them at higher risk for severe disease due to COVID-19.
    • If the child is moderately to severely immunocompromised, offer an age-appropriate dose 21 days (manufacturer's authorized interval) after the invalid dose. Because the series was started at 4 years of age using Pfizer-BioNTech Comirnaty, the moderately to severely immunocompromised child requires 4 doses in the primary series. Offer the third valid dose with a 4 to 8 week interval from the repeat dose and the fourth valid dose with a 4 to 8 week interval from the third valid dose. Offer a booster dose 6 months from the fourth valid dose as per NACI recommendations.
    • Note that when starting a series in those 6 months to 4 years of age who are moderately to severely immunocompromised, NACI prefers Moderna Spikevax as it only requires 3 doses, instead of 4 doses for Pfizer-BioNTech Comirnaty (see Recommendations on the use of Pfizer-BioNTech Comirnaty [3 mcg] COVID-19 vaccine in children 6 months to 4 years of age).
Product administered for the first dose of the primary series to a child 4 years of age was a 3 mcg dose of Pfizer-BioNTech Comirnaty and the child, now 5 years of age, received 10 mcg of Pfizer-BioNTech Comirnaty for dose 2
  • Consider the second dose valid.
    • Because the series was started at 4 years of age with Pfizer-BioNTech Comirnaty, the immunocompetent child requires 3 doses in the primary series. Offer the third dose at least 8 weeks from the second dose. A booster dose 6 months from the third dose should or may be offered as per NACI recommendations, depending on if the child has underlying medical conditions that put them at higher risk for severe disease due to COVID-19.
    • Because the series was started at 4 years of age using Pfizer-BioNTech Comirnaty, the moderately to severely immunocompromised child requires 4 doses in the primary series. Offer the third dose with a 4 to 8 week interval from the second dose and offer the fourth dose with a 4 to 8 week interval from the third dose. Offer a booster dose 6 months from the fourth dose as per NACI recommendations.
    • Note that when starting a series in those 6 months to 4 years of age who are moderately to severely immunocompromised, NACI prefers Moderna Spikevax as it only requires 3 doses, instead of 4 doses for Pfizer-BioNTech Comirnaty (see Recommendations on the use of Pfizer-BioNTech Comirnaty [3 mcg] COVID-19 vaccine in children 6 months to 4 years of age).
Product administered as a first dose of the primary series to a child 5 years of age was a 10 mcg dose of Pfizer-BioNTech Comirnaty (authorized dose) or a 25 mcg dose of Moderna Spikevax (authorized dose) and dose 2 administered at 6 years of age was Moderna Spikevax 25 mcg (lower than authorized dose)
  • Consider the dose valid.
  • However, if the error is discovered in time, an additional dose of Moderna Spikevax 25 mcg may be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
    • Inform the client of the potential for local and systemic adverse events with the repeat dose.
    • If the additional 25 mcg cannot be given on the same clinic day, do not give an additional dose.
  • If the client is moderately to severely immunocompromised and requires an additional dose in the primary series, give it with a recommended full age-appropriate dosage and product at 4 to 8 weeks from the second dose.
  • A booster dose 6 months from the completion of the primary series should or may be offered as per NACI recommendations, depending on if the child has underlying medical conditions that put them at higher risk for severe disease due to COVID-19.
  • Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 6 to 11 year olds due to a lower risk of myocarditis/pericarditis.
Product administered as a first dose of the primary series to a child 6 years of age was Moderna Spikevax 25 mcg (lower than authorized dose) and dose 2 administered at 6 years of age was Moderna Spikevax 25 mcg (lower than authorized dose)
  • Consider the second dose invalid. Clinical judgment is required to determine if the first dose should be accepted. In this example, it seems reasonable to accept the first dose.
  • If the error regarding the second dose is discovered in time, an additional dose of Moderna Spikevax 25 mcg may be offered on the same clinic day (which is in addition to the 25 mcg they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day, offer a full age-appropriate dose 28 days (manufacturer's authorized interval) following the invalid second dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the client is moderately to severely immunocompromised and requires an additional dose in the primary series, give it with a recommended age-appropriate dosage and product at 4 to 8 weeks after the valid second dose.
  • A booster dose 6 months from the completion of the primary series should or may be offered as per NACI recommendations, depending on if the child has underlying medical conditions that put them at higher risk for severe disease due to COVID-19.
  • Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 6 to 11 year olds due to a lower risk of myocarditis/pericarditis.
Product administered to a child 7 to 11 years of age was a 25 mcg dose of Moderna Spikevax (lower than authorized dose) as part of the primary series
  • Consider the dose invalid.
    • Note if more than 1 dose in the primary series was given as 25 mcg to a child 7 to 11 years of age, the latest dose should be considered invalid, and clinical judgment is required to determine if the earlier doses should be accepted or considered invalid.
  • If the error is discovered in time, a 25 mcg Moderna Spikevax dose should be offered on the same clinic day (which is in addition to the 25 mcg they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day:
    • Offer a full age-appropriate (50 mcg) dose 28 days (manufacturer's authorized interval) following the invalid dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the child requires a subsequent dose in the primary series or a booster dose, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
  • Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 6 to 11 year olds due to a lower risk of myocarditis/pericarditis.
Adolescents 12 to 17 years of age

Guiding principles for adolescents 12 to 17 years of age

Primary series age transitions

If while receiving their primary series, an adolescent transitions from 11 to 12 years of age, NACI recommends that they should receive the appropriate dose for their current age. For those who are immunocompetent, this is a 2-dose series and for those who are moderately to severely immunocompromised, it is a 3-dose series.

  • For Pfizer-BioNTech Comirnaty, they should receive 10 mcg when they are 11 years of age and 30 mcg when they are 12 years of age.
  • For Moderna Spikevax, they should receive 50 mcg when they are 11 years of age and 100 mcg when they are 12 years of age.
  • Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series in adolescents 12 to 17 years of age due to a lower risk of myocarditis/pericarditis.

NACI recommends that monovalent original vaccines be used for the primary series. A bivalent Omicron-containing vaccine inadvertently used in the primary series in an adolescent is considered valid (consistent with Updated guidance on COVID-19 vaccine booster doses in Canada), assuming a valid dose was used (i.e., 30 mcg of Pfizer-BioNTech bivalent or 50 mcg of Moderna Spikevax bivalent).

Booster doses

As per the Updated guidance on COVID-19 vaccine booster doses in Canada, a bivalent booster dose should be offered to adolescents 12 to 17 years of age who are part of high risk groups and may be offered to other adolescents (see the recommendations for boosters in the Canadian Immunization Guide: COVID-19 vaccines for detailed recommendations). For booster doses in those 12 years of age and over, bivalent Omicron-containing vaccines are preferred (Updated guidance on COVID-19 vaccine booster doses in Canada).

The Pfizer-BioNTech Comirnaty bivalent vaccine (30 mcg) is the only authorized bivalent booster for those 12 to 17 years of age. NACI has indicated that Moderna Spikevax bivalent (50 mcg) may be offered off-label to adolescents 12 to 17 years of age who are moderately to severely immunocompromised, based on clinical discretion (Updated guidance on COVID-19 vaccine booster doses in Canada).

  • Although not authorized, if the Moderna Spikevax bivalent vaccine (50 mcg) was used as a booster dose for adolescents 12 to 17 years of age, it would be considered valid (PHAC recommendation).
  • Although not the preferred products, if the monovalent original vaccine of either Pfizer-BioNTech Comirnaty (30 mcg) or Moderna Spikevax (50 mcg) were used for a booster dose for adolescents 12 to 17 years of age, they would be considered valid (PHAC recommendation and consistent with Updated guidance on COVID-19 vaccine booster doses in Canada).
The dose is known to be too low

For Pfizer-BioNTech Comirnaty, in adolescents 12 to 17 years of age, the age-appropriate dose for the primary series and the booster dose is 30 mcg. For error management, any dose less than 30 mcg is considered invalid (PHAC recommendation). This recommendation is provided because a dose of Pfizer-BioNTech Comirnaty less than 30 mcg may not result in an optimal response. Note that if more than 1 dose in the primary series was discovered to be invalid, clinical judgment will be required about whether to repeat earlier doses.

For Moderna Spikevax, the age-appropriate dose for adolescents 12 to 17 years of age is 100 mcg for the primary series and 50 mcg for the booster dose. For error management, a 50 mcg dose is considered valid for any dose in adolescents 12 to 17 years of age. Any dose lower than 50 mcg is considered invalid (PHAC recommendation). This recommendation is provided because a dose of 50 mcg of Moderna Spikevax is expected to induce an adequate response in this age group. Note that if more than 1 dose in the primary series was discovered to be invalid (less than 50 mcg), clinical judgment will be required about whether to repeat earlier doses.

Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 12 to 17 year olds due to a lower risk of myocarditis/pericarditis.

  • If the error of too low a dose resulting in an invalid dose is discovered in time, offer a repeat dose on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb). See examples for possible dosage to use for the repeat dose.
  • If the repeat dose cannot be given on the same clinic day:
    • If Pfizer-BioNTech Comirnaty is the invalid dose and it is the first dose in the primary series, repeat immediately once recognized with a full age-appropriate dose. If Pfizer-BioNTech Comirnaty is the invalid dose (less than 30 mcg) and it is the second dose (or a third dose for those who are moderately to severely immunocompromised), repeat 21 days (manufacturer's authorized interval) after the invalid dose using a full age-appropriate dose. This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events.
    • If Moderna Spikevax is the invalid dose (less than 50 mcg) and it is any dose in the primary series, repeat 28 days (manufacturer's authorized interval) after the invalid dose using a full age-appropriate dose. This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events. (Note NACI's preference for Pfizer-BioNTech Comirnaty for the primary series in those 12 to 17 years of age).
    • If the invalid dose is a booster dose, repeat 8 weeks after the invalid dose using a full age-appropriate bivalent Omicron-containing booster dose. The waiting period is intended to avoid interference with the response that may develop to the invalid booster dose. (Note Pfizer-BioNTech Comirnaty is the only bivalent Omicron-containing booster dose authorized for those 12 to 17 years of age. NACI has indicated that Moderna Spikevax bivalent [50 mcg] may be offered off-label to adolescents 12 to 17 years of age who are moderately to severely immunocompromised, based on clinical discretion [Updated guidance on COVID-19 vaccine booster doses in Canada]).
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the adolescent requires a subsequent dose in the primary series or a booster dose, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose.

Examples

Product administered to an adolescent 12 to 17 years of age was a 10 mcg dose of Pfizer-BioNTech Comirnaty (rather than the recommended 30 mcg dose) as part of a primary series
  • Consider the dose invalid.
    • Note if more than 1 dose in the primary series was given as 10 mcg to an adolescent 12 to 17 years of age, the latest dose should be considered invalid, and clinical judgment is required to determine if the earlier doses should be accepted or considered invalid.
  • If the error is discovered in time, a full repeat age-appropriate dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day:
    • If the 10 mcg dose is the first dose in the primary series, offer a full age-appropriate dose immediately.
    • If the 10 mcg dose is the second (or third dose for those who are moderately to severely immunocompromised), offer a full age-appropriate dose 21 days (manufacturer's authorized interval) following the invalid dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
Product administered to an adolescent 12 to 17 years of age was a 10 mcg dose of Pfizer-BioNTech Comirnaty (monovalent original or bivalent) [rather than the recommended 30 mcg dose] for a booster dose
  • Consider the dose invalid.
  • If the error is discovered in time, offer a full dose of Pfizer-BioNTech Comirnaty bivalent Omicron-containing vaccine on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be given on the same clinic day, wait 8 weeks to offer a Pfizer-BioNTech Comirnaty bivalent Omicron-containing booster dose with the recommended age-appropriate dosage.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
Product administered to an adolescent 12 to 17 years of age was a 50 mcg dose of Moderna Spikevax (rather than the recommended 100 mcg dose) for any or all dose(s) of the primary series
  • Consider the dose(s) valid.
    • However, if the error is discovered in time, an additional dose of Moderna Spikevax 50 mcg may be offered on the same clinic day (which is in addition to the 50 mcg they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
    • If the additional 50 mcg cannot be given on the same clinic day, do not give an additional dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
  • Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 12 to 17 year olds due to a lower risk of myocarditis/pericarditis.
Product administered to an adolescent 12 to 17 years of age was a 25 mcg dose of Moderna Spikevax (lower than authorized dose) as part of a primary series
  • Consider the dose invalid.
  • If the error is discovered in time so that the repeat dose can be given on the same clinic day:
    • Consider offering a full age-appropriate dose of Pfizer-BioNTech Comirnaty (30 mcg) [which is the preferred product for those 12 to 17 years of age as per NACI recommendations] in a separate anatomic injection site whenever possible (e.g., different limb).
    • If offering Moderna Spikevax, a 75 mcg dose may be used (which is in addition to the 25 mcg dose they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the additional dose cannot be given on the same clinic day:
    • Offer a full age-appropriate dose 28 days (manufacturer's authorized interval) following the invalid dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
  • Note that NACI prefers Pfizer-BioNTech Comirnaty for the primary series for 12 to 17 year olds due to lower risk of myocarditis/pericarditis.
Product administered to an adolescent 12 to 17 years of age was a 25 mcg dose of Moderna Spikevax (rather than the recommended 50 mcg dose) for a booster dose
  • Consider the dose invalid.
  • If the error is discovered in time so that the repeat dose can be given on the same clinic day:
    • If offering Pfizer-BioNTech Comirnaty bivalent Omicron-containing vaccine, 30 mcg can be given in a separate anatomic injection site whenever possible (e.g., different limb).
    • If offering Moderna Spikevax bivalent Omicron-containing vaccine, a 25 mcg dose can be given (which is in addition to the 25 mcg dose they already received) in a separate anatomic injection site whenever possible (e.g., different limb)
  • If the dose cannot be given on the same clinic day, wait 8 weeks after the invalid dose to offer a full age-appropriate bivalent Omicron-containing booster dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.

Note: The Pfizer-BioNTech Comirnaty bivalent vaccine (30 mcg) is the only authorized bivalent booster for those 12 to 17 years of age. NACI has indicated that Moderna Spikevax bivalent (50 mcg) may be offered off-label to adolescents 12 to 17 years of age who are moderately to severely immunocompromised, based on clinical discretion (Updated guidance on COVID-19 vaccine booster doses in Canada).

Adolescent inadvertently received a bivalent Omicron-containing vaccine (any bivalent product assuming a valid dose was used i.e., 30 mcg of Pfizer-BioNTech Comirnaty bivalent or 50 mcg of Moderna Spikevax bivalent) for one or all doses of their primary series
  • Consider the dose valid.
    • However, if the dose of Moderna Spikevax bivalent Omicron-containing vaccine was 50 mcg and it is discovered in time, an additional dose of monovalent original Moderna Spikevax 50 mcg may be offered on the same clinic day (which is in addition to the 50 mcg bivalent Omicron-containing dose they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
    • If the additional 50 mcg of monovalent original Moderna Spikevax dose cannot be given on the same clinic day, do not give an additional dose.
  • If the client requires a subsequent dose in the primary series or a booster dose, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
  • Note that Pfizer-BioNTech Comirnaty is the preferred product for 12 to 17 years of age for the primary series due to the lower risk of myocarditis/pericarditis.
Adolescent received the monovalent original vaccine for their booster dose
  • Consider the dose valid.
  • If the client requires a subsequent booster dose, give it with a bivalent Omicron-containing product, following the recommended age-appropriate dosage and follow the suggested optimal interval from the valid dose.
  • Note that Pfizer-BioNTech Comirnaty is the only bivalent Omicron-containing booster dose authorized for 12 to 17 year olds. NACI has indicated that Moderna Spikevax bivalent (50 mcg) may be offered off-label to adolescents 12 to 17 years of age who are moderately to severely immunocompromised, based on clinical discretion (Updated guidance on COVID-19 vaccine booster doses in Canada).
Adults 18 years of age and older

Guiding principles for adults 18 years of age and over

Primary series

For adults who are immunocompetent, a primary series consists of 2 doses of most COVID-19 vaccines (1 dose of Janssen) and for those who are moderately to severely immunocompromised, a primary series consists of 3 doses of most COVID-19 vaccines (1 dose of Janssen plus 1 original mRNA dose) [see Canadian Immunization Guide for schedule of COVID-19 vaccines]. For the mRNA vaccines (which are the preferred COVID-19 vaccines as per the Canadian Immunization Guide schedule of COVID-19 vaccines), the monovalent original vaccine is recommended for the primary series. NACI prefers Pfizer-BioNTech for the primary series for those 18 to 29 years of age due to the lower risk of myocarditis/pericarditis.

A bivalent Omicron-containing vaccine inadvertently used in the primary series in an adult is considered valid (consistent with Updated guidance on COVID-19 vaccine booster doses in Canada), assuming a valid dose was used for the primary series (i.e., 30 mcg of Pfizer-BioNTech Comirnaty bivalent or 50 mcg of Moderna Spikevax bivalent).

Authorized doses for adults are listed in Recommendations for adults 18 years of age and older in the Canadian Immunization Guide: COVID-19 vaccines.

Booster doses

Previously, NACI has recommended a booster dose should be offered for everyone 18 years of age and over. In the fall of 2022, the following regarding fall booster doses was recommended (Updated guidance on COVID-19 vaccine booster doses in Canada):

  • Adults ≥65 years of age should be offered a fall COVID-19 booster dose.
  • Adults 12 to 64 years of age who are at increased risk of severe illness from COVID-19 should be offered a fall COVID-19 booster dose. Other adults 12 to 64 years of age may be offered a fall COVID-19 vaccine booster dose.
  • Bivalent Omicron-containing vaccines are the preferred booster dose products for those ≥12 years of age.
  • Either the Moderna Spikevax BA.1 (50 mcg) bivalent vaccine or Pfizer-BioNTech BA.4/5 (30 mcg) bivalent vaccine can be used as the bivalent booster dose for the ages that they are authorized.

Although not the preferred products, if the monovalent original vaccine of either Pfizer-BioNTech Comirnaty or Moderna Spikevax are used for a booster dose, they are considered valid (PHAC recommendation and consistent with Updated guidance on COVID-19 vaccine booster doses in Canada).

The dose is known to be too low

Authorized doses for adults are listed in Recommendations for adults 18 years of age and older in the Canadian Immunization Guide: COVID-19 vaccines.

For Pfizer-BioNTech Comirnaty, in adults 18 years of age and older, the age-appropriate dose for the primary series and the booster dose is 30 mcg. For error management, any dose less than 30 mcg is considered invalid (PHAC recommendation). This recommendation is provided because a dose of Pfizer-BioNTech Comirnaty less than 30 mcg may not result in an optimal response. Note that if more than 1 dose in the primary series was discovered to be invalid, clinical judgment will be required about whether to repeat earlier doses.

For Moderna Spikevax, the age-appropriate dose for adults 18 years of age and older is 100 mcg for the primary series and 50 mcg for the booster dose. For error management, a 50 mcg dose is considered valid for any dose in adults 18 years of age and older. Any dose lower than 50 mcg is considered invalid (PHAC recommendation). This recommendation is provided because a dose of 50 mcg of Moderna Spikevax is expected to induce an adequate response in this age group. Note that if more than 1 dose in the primary series was discovered to be invalid (less than 50 mcg), clinical judgment will be required about whether to repeat earlier doses.

If the error resulting in an invalid dose is discovered in time, a repeat dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb). See examples for possible dosages to use for the repeat dose.

  • If the repeat dose cannot be given on the same clinic day:
    • If Pfizer-BioNTech Comirnaty is the invalid dose and it is the first dose in the primary series, repeat immediately once recognized with a full age-appropriate dose. If Pfizer-BioNTech Comirnaty is the invalid dose and it is the second dose (or third dose for those who are moderately to severely immunocompromised), repeat 21 days (manufacturer's authorized interval) after the invalid dose using a full age-appropriate dose. This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events.
    • If Moderna Spikevax is the invalid dose and it is any dose in the primary series, repeat 28 days (manufacturer's authorized interval) after the invalid dose using a full age-appropriate dose. This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events. (Note NACI's preference for Pfizer-BioNTech Comirnaty for the primary series in those 18 to 29 years of age).
    • If the invalid dose is a booster dose, repeat 8 weeks after the invalid dose using a full age-appropriate bivalent Omicron-containing dose. The waiting period is intended to avoid interference with the response that may develop to the invalid booster dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the client requires a subsequent dose in the primary series or a booster dose, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose.

Examples

Product administered is a 10 mcg dose of Pfizer-BioNTech Comirnaty (less than the authorized dose) for a primary series dose
  • Consider the dose invalid.
  • If the error is discovered in time, offer 30 mcg of Pfizer-BioNTech Comirnaty on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day:
    • If the invalid dose is the first dose in the primary series, offer an age-appropriate dose immediately.
    • If the invalid dose is the second (or third dose for those who are moderately to severely immunocompromised), offer an age-appropriate dose 21 days (manufacturer's authorized interval) following the invalid dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
Product administered is a 10 mcg dose of Pfizer-BioNTech Comirnaty (monovalent original or bivalent Omicron-containing) [less than the 30 mcg authorized dose] for the booster dose
  • Consider the dose invalid.
  • If the error is discovered in time, offer a 30 mcg dose of Pfizer-BioNTech Comirnaty bivalent Omicron-containing booster dose on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day, wait 8 weeks to offer a repeat booster dose with the recommended age-appropriate dosage of a bivalent Omicron-containing product.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
Product administered is a 50 mcg dose of Moderna Spikevax (less than the authorized dose) for a primary series dose
  • Consider the dose valid.
    • If the error is discovered in time, offer 50 mcg of the monovalent original Moderna Spikevax vaccine on the same clinic day (which is in addition to the 50 mcg they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
    • If the additional 50 mcg of monovalent original Moderna Spikevax dose cannot be given on the same clinic day, do not give an additional dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
  • Note that NACI prefers Pfizer-BioNTech for the primary series for those 18 to 29 years of age due to the lower risk of myocarditis/pericarditis.
Product administered is a 25 mcg dose of Moderna Spikevax (less than the authorized dose) for a primary series dose
  • Consider the dose invalid.
    • If the error is discovered in time, offer 75 mcg of the monovalent original Moderna Spikevax vaccine on the same clinic day (which is in addition to the 25 mcg they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day:
    • Offer a full age-appropriate dose 28 days (manufacturer's authorized interval) following the invalid dose.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.
  • Note that NACI prefers Pfizer-BioNTech for the primary series for those 18 to 29 years of age due to the lower risk of myocarditis/pericarditis.
Product administered is a 25 mcg dose of Moderna Spikevax (monovalent original or bivalent Omicron-containing) [less than the 50 mcg authorized dose] for the booster dose
  • Consider the dose invalid.
  • If the error is discovered in time, offer a 25 mcg dose of Moderna Spikevax bivalent Omicron-containing booster dose on the same clinic day (which is in addition to the 25 mcg they already received) in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day, wait 8 weeks to offer a repeat booster dose with the recommended full age-appropriate dosage of a bivalent Omicron-containing product.
  • Inform the client of the potential for local and systemic adverse events with the repeat dose.
Adult inadvertently received a bivalent Omicron-containing vaccine (any bivalent product) for one or all dose(s) of their primary series, assuming a valid dose was used for the primary series (i.e., 30 mcg of Pfizer-BioNTech Comirnaty bivalent or 50 mcg of Moderna Spikevax bivalent)
  • Consider the dose(s) valid.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the valid dose.

Note: If the dose was less than the 100 mcg Moderna Spikevax bivalent Omicron-containing product, manage as per example: "Product administered is a 50 mcg dose of Moderna Spikevax (less than the authorized dose) for a primary series dose".

Adult received the monovalent original vaccine for their booster dose
  • Consider the dose(s) valid.
  • If the client requires a subsequent booster dose, give it with a recommended age-appropriate dosage, bivalent Omicron-containing product and follow the suggested optimal interval from the valid dose.

Co-administration

Guiding principles for co-administration

NACI recommends that for individuals 5 years of age and older, COVID-19 vaccines may be given concurrently with (i.e., same day), or at any time before or after, non-COVID-19 vaccines (including live and non-live vaccines). With regard to Imvamune (for the prevention of monkeypox), NACI has issued some precautionary suggestions regarding the timing of this vaccine relative to COVID-19 vaccines.

NACI recommends at this time that the Moderna Spikevax (25 mcg) primary series for children 6 months to 5 years of age or the Pfizer-BioNTech Comirnaty (3 mcg) primary series for children 6 months to 4 years of age should not routinely be given concurrently (i.e., same day) with other vaccines (live or non-live). For this age group, it is advised to wait 14 days when administering a COVID-19 vaccine and other vaccines. This waiting period is precautionary. Concurrent vaccination or a shorter interval between COVID-19 vaccines and other vaccines may be warranted on an individual basis in some circumstances at the clinical discretion of the healthcare provider (NACI statement).

Doses of COVID-19 vaccines and other vaccines that are given concurrently or at less than a 14-day interval to children 6 months to 5 years of age are considered valid (PHAC recommendation).

Examples

COVID-19 vaccine administered on the same day or within 14 days before or after a non-COVID-19 vaccine (for children, adolescents or adults)
  • Both the COVID-19 and the other vaccine are valid.
COVID-19 vaccine administered simultaneously with monoclonal antibodies or convalescent plasma
  • Assessment in consultation with a clinical expert should be sought on a case-by-case basis.

Interval errors

Guiding principle for doses given longer than the optimal interval

Generally it is recommended to use the optimal interval between doses, however there is no interval that is too long, and all doses beyond the optimal interval are considered valid, whether for the primary series, including for moderately to severely immunocompromised people, or for the booster.

See the Canadian Immunization Guide for optimal intervals for COVID-19 vaccines.

Guiding principle for doses given earlier than the minimum interval

Doses given too close together may not result in an optimal immune response because:

  1. less than optimal time to allow for the immune response to mature between doses, and
  2. antibodies produced to the early dose may interfere with the antibody response to the later dose.
Primary series

Doses given closer together than the minimum interval in the primary series are considered invalid. However, it should be noted that an immune response will develop from this invalid dose. Therefore, in order to avoid interference with this developing immune response, a repeat dose is recommended as follows:

  • For non-immunocompromised individuals, wait 8 weeks (or at least 8 weeks for those 6 months to 11 years of age) to repeat the dose in the primary series.
  • For moderately to severely immunocompromised individuals, wait 4 to 8 weeks to repeat the dose in the primary series.
  • Offer an age-appropriate product and dosage for the repeat dose.

To determine the minimum interval for primary series, refer to the Canadian Immunization Guide tables containing the schedule for the primary series or the schedule for the primary series for individuals who are moderately to severely immunocompromised. For mixed COVID-19 vaccine schedules (more than 1 product used in the primary series), the minimum interval should be based on the minimum interval of the product used for the first dose (see the Canadian Immunization Guide tables containing the schedule for the primary series).

Booster doses
  • As long as at least 8 weeks has passed since the last dose (i.e., primary series or preceding booster) and the current booster, consider the current booster dose valid.
  • If less than 8 weeks has passed since the last dose (i.e., primary series or preceding booster) and the current booster, consider the current booster dose invalid and repeat the booster dose 6 months from the invalid dose. Offer an age-appropriate bivalent Omicron-containing product for the repeat booster.

Examples

Primary series

Doses in the primary series were administered sooner than the minimum interval for the vaccine product

  • Consider the most recent dose invalid.
  • Wait 8 weeks (or at least 8 weeks for those 6 months to 11 years of age) to offer the repeat dose for immunocompetent individuals and 4 to 8 weeks for moderately to severely immunocompromised individuals. Offer an age-appropriate product and dosage.
  • When repeating the dose, inform the client of the potential for local and systemic adverse events.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose.
Boosters

A booster dose given at less than a 3- to 6-month interval from the last dose in the primary series or the preceding booster

  • As long as at least 8 weeks has passed since the last dose (i.e., primary series or preceding booster) and the current booster, consider the current booster dose valid.
  • If less than 8 weeks has passed since the last dose (i.e., primary series or preceding booster) and the current booster, consider the current booster dose invalid and repeat the booster dose 6 months from the invalid dose. Offer an age-appropriate bivalent Omicron-containing product for the repeat booster.

Storage and handling errors, including reconstitution errors

Guiding principles for storage and handling errors, including reconstitution errors

Storage and handling errors or deviations require individual consideration based on the particular circumstances, in consultation with the manufacturer and based on clinical judgment.

In consulting with the manufacturer, inquire if they have any specific information related to the storage and handling of the particular error or deviation involving the specific product or lot or more general information that may help to inform decisions regarding the error or deviation. In addition to information from the manufacturer, other factors to consider in deciding whether a dose requires repeating and when it should be repeated include:

  • How substantial was the deviation? (e.g., how long was the product exposed to an inappropriate temperature and what was the temperature deviation? How much over diluted was the product?)
  • How many other doses has the client received, and when are they scheduled to receive their next dose if the dose is not repeated?
  • Were there any other errors or deviations in the client's previous doses?
  • What are the client's underlying COVID-19-related risk factors for serious COVID-19 disease or a less than an optimal response to the vaccine (e.g., age, underlying medical conditions or immunocompromising conditions)?
  • Has the client had any significant adverse events after previous doses?

If it is deemed appropriate to repeat a dose, judgment is required as to the timing of the repeat dose.

  • If the error is discovered in time, a repeat age-appropriate dose for an invalid dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day:
    • A repeat age-appropriate dose after an invalid dose that may have some residual potency may be offered at a longer interval (e.g., up to 8 weeks from the invalid dose in immunocompetent individuals, or 4 to 8 weeks in moderately to severely immunocompromised individuals for the primary series, or up to 8 weeks for the booster dose) in order not to interfere with a response that may result from the invalid dose.
    • A repeat age-appropriate dose after an invalid dose that is expected to have little remaining potency may be offered as follows:
      • If the invalid dose is a Pfizer-BioNTech Comirnaty first dose in the primary series, the repeat dose may be offered immediately. If it is Pfizer-BioNTech Comirnaty and it is a second or subsequent dose, including a booster dose, repeat the dose at the manufacturer's authorized interval for the primary series (i.e., 21 days for Pfizer-BioNTech Comirnaty) from the invalid dose.
      • If the invalid dose is Moderna Spikevax for any dose, including a booster dose, offer a repeat dose at the manufacturer's authorized interval for the primary series (i.e., 28 days for Moderna Spikevax) from the invalid dose.

To determine the manufacturer's authorized interval, refer to the Canadian Immunization Guide tables containing the schedule for the primary series.

Examples

Dose administered after improper storage and handling, including temperature excursions or use beyond the expiry date
  • Contact the manufacturer for guidance, as well as your local public health authority for advice.
  • If the manufacturer provides information suggesting the dose should be considered invalid and if that seems appropriate based on clinical judgment, a repeat age-appropriate dose may be given.
  • If the error is discovered in time, a repeat age-appropriate dose for an invalid dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day:
    • A repeat age-appropriate dose after an invalid dose that may have some residual potency may be offered at a longer interval (e.g., up to 8 weeks from the invalid dose in immunocompetent individuals, or 4 to 8 weeks in moderately to severely immunocompromised individuals for the primary series, or up to 8 weeks for the booster dose) in order not to interfere with a response that may result from the invalid dose.
    • A repeat age-appropriate dose after an invalid dose that is expected to have little remaining potency may be offered as follows:
      • If the invalid dose is a Pfizer-BioNTech Comirnaty first dose in the primary series, the repeat dose may be offered immediately. If it is Pfizer-BioNTech Comirnaty and it is a second or subsequent dose, including a booster dose, repeat the dose at the manufacturer's authorized interval for the primary series (i.e., 21 days for Pfizer-BioNTech Comirnaty) from the invalid dose.
      • If the invalid dose is Moderna Spikevax for any dose, including a booster dose, offer a repeat dose at the manufacturer's authorized interval for the primary series (i.e., 28 days for Moderna Spikevax) from the invalid dose.
  • Inform the client of the potential for local and systemic adverse events if repeating a dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose.
Incorrect diluent type (e.g., sterile water instead of 0.9% sodium chloride for Pfizer-BioNTech Comirnaty reconstitution)
  • Contact the manufacturer for guidance, as well as your local public health authority for advice.
  • If the manufacturer provides information suggesting that the dose should be considered invalid and if that seems appropriate based on clinical judgment, a repeat age-appropriate dose may be given.
  • If the error is discovered in time, a repeat age-appropriate dose for an invalid dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb).
  • If the dose cannot be repeated on the same clinic day, discuss with the manufacturer the likelihood that the vaccine will maintain some potency and base the decision on the timing of the repeat dose on this information:
    • A repeat age-appropriate dose after an invalid dose that may have some residual potency may be offered at a longer interval (e.g., up to 8 weeks from the invalid dose in immunocompetent individuals, or 4 to 8 weeks in moderately to severely immunocompromised individuals for the primary series, or up to 8 weeks for the booster dose) in order not to interfere with a response that may result from the invalid dose.
    • A repeat age-appropriate dose after an invalid dose that is expected to have little remaining potency may be offered as follows:
      • If the invalid dose is a Pfizer-BioNTech Comirnaty first dose in the primary series, the repeat dose may be offered immediately. If it is Pfizer-BioNTech Comirnaty and it is a second or subsequent dose, including a booster dose, repeat the dose at the manufacturer's authorized interval for the primary series (i.e., 21 days for Pfizer-BioNTech Comirnaty) from the invalid dose
      • If the invalid dose is Moderna Spikevax for any dose, including a booster dose, offer a repeat dose at the manufacturer's authorized interval for the primary series (i.e., 28 days for Moderna Spikevax) from the invalid dose.
  • Inform the client of the potential for local and systemic adverse events if repeating a dose.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose.
Only diluent administered

Situation: Only the diluent (0.9% sodium chloride) was administered:

  • inform the client that no vaccine was administered
  • offer an authorized (appropriately diluted) dose as soon as possible in the same or another appropriate site
Too much diluent administered resulting in a lower than authorized dose

Situations:

  • more than 2.2 ml of diluent was added to the Pfizer-BioNTech Comirnaty maroon-capped vaccine vial (3 mcg dose for children 6 months to 4 years of age), based on 0.2 ml dose administered, or
  • more than 1.3 ml of diluent was added to the Pfizer-BioNTech Comirnaty orange-capped vaccine vial (10 mcg dose for children 5 to 11 years of age), based on 0.2 ml dose administered, or
  • more than 2.0 ml of diluent (noting recommended volume for diluent is 1.8 ml) was added to the Pfizer-BioNTech Comirnaty purple-capped vaccine vial (30 mcg dose for those 12 years of age and over), based on 0.3 ml dose administered, or
  • any diluent was added to the Pfizer-BioNTech Comirnaty 30 mcg grey-capped vaccine vials (monovalent original or bivalent Omicron-containing vaccine) or any Moderna Spikevax product (these products should not be diluted)

In these situations:

  • consider the dose invalid
  • if the error is discovered in time, a repeat age-appropriate dose should be offered on the same clinic day in a separate anatomic injection site whenever possible (e.g., different limb)
  • if the dose cannot be repeated on the same clinic day, the time to repeat the dose is based on clinical judgment depending on the extent of over dilution:
    • if only a small amount of extra diluent was added, a repeat age-appropriate dose after an invalid dose may be offered after a longer interval (e.g., up to 8 weeks from the invalid dose in immunocompetent individuals, or 4 to 8 weeks in moderately to severely immunocompromised individuals for the primary series, or up to 8 weeks for the booster dose) in order not to interfere with a response that may result from the invalid dose
    • if a large amount of extra diluent was added, a repeat age-appropriate dose may be offered as follows:
      • If the invalid dose is a Pfizer-BioNTech Comirnaty first dose in the primary series, the repeat dose may be offered immediately. If it is Pfizer-BioNTech Comirnaty and it is a second or subsequent dose, including a booster dose, repeat the dose at the manufacturer's authorized interval for the primary series (i.e., 21 days for Pfizer-BioNTech Comirnaty) from the invalid dose.
      • If the invalid dose is Moderna Spikevax for any dose, including a booster dose, offer a repeat dose at the manufacturer's authorized interval for the primary series (i.e., 28 days for Moderna Spikevax) from the invalid dose.
  • inform the client of the potential for local and systemic adverse events with the repeat dose
  • if the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose
No diluent or less than recommended diluent resulting in a higher than authorized dose for Pfizer-BioNTech Comirnaty products that require a diluent
  • Consider the dose valid.
  • Inform the client of the potential for local and systemic adverse events.
  • If the client requires a subsequent dose in the primary series or a booster, give it with a recommended age-appropriate dosage and product and follow the suggested optimal interval from the repeat dose.
No adjuvant or less than recommended adjuvant (Medicago) – Note that this product is not currently available
  • Consider the dose invalid.
  • If the error is discovered on the same clinic day, offer a full authorized dose (e.g., appropriately mixed with adjuvant) immediately in a separate anatomic injection site whenever possible (e.g., different limb).
  • Inform the person of the potential for local and systemic adverse events.
  • Contact the manufacturer if additional guidance is needed. Your local public health authority can also be consulted for advice.
Only adjuvant administered (Medicago) – Note that this product is not currently available
  • Inform the client that no vaccine was administered.
  • Offer an appropriately reconstituted full repeat dose as soon as the error is recognized. If this is the same day as only the adjuvant was administered, use a separate anatomic injection site whenever possible (e.g., different limb).
  • Inform the client of the potential for local and systemic adverse events

More or less than authorized number of doses obtained from vial
  • Depending on the type of supplies used (e.g., low dead volume syringe) the number of doses obtained from vials may vary.
  • As long as the correct volume was drawn up per dose (and the correct amount of diluent was used if the product required dilution), the doses are valid.

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