Planning guidance for immunization clinics for COVID-19 vaccines: Managing vaccine administration errors or deviations
On this page
- Preamble
- Strategies to prevent COVID-19 vaccine errors or deviations
- What to do after an error or deviation is detected
- Type of administration errors and deviations: Guiding principles and recommended actions
Preamble
This website is for health care providers. It offers an approach to preventing and 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 of the National Advisory Committee on Immunization (NACI). These are referred to as vaccine administration errors or deviations.
The Canadian Immunization Committee provided input into the development of this document.
For complete NACI advice, please see the following:
Note that this document should be used only to manage errors or deviations that have already occurred, and should not be used to justify practices that are different than what are recommended based on provincial or territorial guidance, the product monographs or recommendations from NACI statements and publications when administering COVID-19 vaccines.
Strategies to prevent COVID-19 vaccine errors or deviations
Due to the availability of several products, doses, and schedules for COVID-19 vaccines, there is the potential for errors when storing, handling and administering these vaccines. The purpose of this document is to assist with error prevention for COVID-19 vaccines. If you require advice or assistance, contact your local public health department.
These strategies support error prevention in all settings:
- education and training
- policies and procedures
- checklists and job aids
- audits
Error prevention is also supported by:
- an appropriate clinic environment and setup
- not feeling rushed
- not being interrupted or distracted during vaccine preparation and administration
Encourage staff to ask questions, contribute suggestions and double check their practices to create a culture of error prevention.
Staff members should be aware of the importance of recognizing and reporting errors, and encouraged to do so to:
- mitigate the impact of the errors
- prevent similar errors in the future
The process for reporting errors should be made clear to staff members. Any reported errors or near misses should be analyzed to inform adjustments in policies, procedures and training.
Learn more about:
- Pharmaceutical Compounding: Sterile Preparations (US Pharmacopeia)
- Storage requirements for COVID-19 vaccines: Canadian Immunization Guide
- National Vaccine Storage and Handling Guidelines for Immunization Providers 2015: Vaccine storage practices (archived)
- COVID-19 Vaccine Safety Interest Group: Recommendations for Global Implementation of Safe COVID-19 Immunization Practices (PDF, International Medication Safety Network)
Community health care providers
| Stage in the vaccination process | Potential vaccine errors or deviations | Strategies for preventing errors or deviations |
|---|---|---|
Client screening and verification of vaccine eligibility |
|
Ensure client is eligible by verifying their information when they book a vaccination appointment on the phone or through an online electronic system.
Ensure client is eligible by verifying their information on arrival at the office.
|
Storage and handling |
|
Prevent temperature excursions.
Ensure good organization of stored vaccines.
Ensure vaccines are not expired.
Ensure punctured vials are used within the recommended time after first puncture of the vial ("use by" date and time) or discarded.
|
Office setup |
|
Ensure appropriate office setup for preparing and administering vaccines.
Prepare the office for emergencies.
|
Preparation of the vaccine |
|
Ensure proper vaccine preparation.
Use product before its "use by" date and time.
Ensure correct product selection and dose.
|
Administration |
|
Pre-vaccination counseling. Refer to the pre-vaccination section of the Vaccine administration practices chapter of the Canadian Immunization Guide.
Ensure administration of correct vaccine with correct dosage at correct time interval.
Develop a standard protocol if administering more than 1 vaccine to the client.
Ensure appropriate administration technique. Refer to the Vaccine administration practices chapter of the Canadian Immunization Guide.
Preventing needlestick injuries.
|
Documentation |
|
Provide accurate and complete documentation in appropriate formats.
As appropriate, book the next vaccination appointments. Send appointment reminders by phone, text or email. |
Evaluation and continuous quality improvement |
Use continuous improvement processes.
Plan for the response to possible errors.
|
References
- Vaccine Storage and Handling Guidelines (PDF, Ontario Ministry of Health)
- How to Vaccinate: Modern Practices for Vaccine Administration (Immunize Canada)
- ISMP Canada Safety Bulletin: Opportunities to Improve COVID-19 Vaccine Labels
- ISMP Canada Safety Bulletin: Updated Analysis and Shared Learning from COVID-19 Vaccine Errors
- ISMP Canada Safety Bulletin: Preventing Errors with COVID-19 Vaccines: Learning from Vaccine Incidents
- ISMP Canada Safety Bulletin: Pediatric Medication Errors in the Community: A Multi-Incident Analysis includes a sidebar: Preventing Pediatric COVID-19 Vaccine Errors at Mass Vaccination Sites
- Vaccine Administration: Preventing Vaccine Administration Errors (PDF, U.S. Centers for Disease Control and Prevention)
- Recommendations for Global Implementation of Safe COVID-19 Immunization Practices (PDF, International Medication Safety Network initiative: COVID-19 Vaccine Safety Interest Group)
This document was prepared in 2023 by the Ontario Ministry of Health, the Public Health Agency of Canada (PHAC) and the Institute for Safe Medication Practices Canada with input from the Canadian Immunization Committee, and was updated by PHAC in July 2026.
Community pharmacies
| Stage in the vaccination process | Potential vaccine errors or deviations | Strategies for preventing errors or deviations |
|---|---|---|
Client screening and verification of vaccine eligibility |
|
Ensure client is eligible by verifying their information when they book a vaccination appointment on the phone or through an online electronic system.
Ensure client is eligible by verifying their information on arrival at the pharmacy.
Ensure the client gets the right product if multiple vaccines are being offered at the pharmacy.
|
Storage and handling |
|
Prevent temperature excursions.
Ensure good organization of stored vaccine.
Ensure vaccines are not expired.
Ensure punctured vials are used within recommended time after first puncture of the vial ("use by" date and time) or discarded.
|
Pharmacy setup |
|
Ensure appropriate pharmacy setup for preparing and administering vaccines.
Prepare the pharmacy for emergencies.
|
Preparation of the vaccine |
|
Ensure proper vaccine preparation.
Use product before its "use by" date and time.
Ensure correct product selection and dose.
|
Administration |
|
Pre-vaccination counseling. Refer to the pre-vaccination section of the Vaccine administration practices chapter of the Canadian Immunization Guide.
Ensure administration of correct vaccine with correct dosage at correct time interval.
Develop a standard protocol if administering more than 1 vaccine to the client.
Ensure appropriate administration technique. Refer to the pre-vaccination section of the Vaccine administration practices chapter of the Canadian Immunization Guide.
Preventing needlestick injuries.
|
Documentation |
|
Provide accurate and complete documentation in appropriate formats.
As appropriate, book the next vaccination appointments. Send appointment reminders by phone, text or email. |
Evaluation and continuous quality improvement |
Use continuous improvement processes.
Plan for the response to possible errors.
|
References
- Vaccine Storage and Handling Guidelines (PDF, Ontario Ministry of Health)
- How to Vaccinate: Modern Practices for Vaccine Administration (Immunize Canada)
- ISMP Canada Safety Bulletin: Opportunities to Improve COVID-19 Vaccine Labels
- ISMP Canada Safety Bulletin: Updated Analysis and Shared Learning from COVID-19 Vaccine Errors
- ISMP Canada Safety Bulletin: Preventing Errors with COVID-19 Vaccines: Learning from Vaccine Incidents
- ISMP Canada Safety Bulletin: Pediatric Medication Errors in the Community: A Multi-Incident Analysis includes a sidebar: Preventing Pediatric COVID-19 Vaccine Errors at Mass Vaccination Sites
- Vaccine Administration: Preventing Vaccine Administration Errors (PDF, U.S. Centers for Disease Control and Prevention)
- Recommendations for Global Implementation of Safe COVID-19 Immunization Practices (PDF, International Medication Safety Network initiative: COVID-19 Vaccine Safety Interest Group)
This document was prepared in 2023 by the Ontario Ministry of Health, the Public Health Agency of Canada and the Institute for Safe Medication Practices Canada with input from the Canadian Immunization Committee, and was updated by PHAC in July 2026.
Large scale immunization clinics
| Stage in the vaccination process | Potential vaccine errors or deviations | Strategies for preventing errors or deviations |
|---|---|---|
Client screening and verification of vaccine eligibility |
|
Ensure client is eligible by verifying their information when they book a vaccination appointment on the phone or through an online electronic system.
Ensure client is eligible by verifying their information on arrival at the immunization clinic.
Ensure the client gets to the right place if multiple vaccines are being offered at the immunization clinic.
|
Storage and handling |
|
Prevent temperature excursions.
Ensure good organization of stored vaccines (if vaccines are stored at the clinic).
Ensure vaccines are not expired.
Ensure punctured vials are used within the recommended time after first puncture of the vial ("use by" date and time) or discarded.
|
Clinic setup |
|
Ensure appropriate clinic setup.
Avoid vaccine mix-ups and errors in dilution.
Prepare the clinic for emergencies.
|
Preparation of the vaccine |
|
Ensure proper vaccine preparation.
Use product before its "use by" date and time.
Ensure correct product selection and dose.
|
Administration |
|
Pre-vaccination counseling. Refer to the pre-vaccination section of the Vaccine administration practices chapter of the Canadian Immunization Guide.
Ensure administration of correct vaccine with correct dosage at correct time interval.
Develop a standard protocol if administering more than 1 vaccine to the client.
Ensure appropriate administration technique. Refer to the Vaccine administration practices chapter of the Canadian Immunization Guide.
Preventing needlestick injuries.
|
Documentation |
|
Provide accurate and complete documentation in appropriate formats.
As appropriate, advise the client to book their next vaccination appointments. |
Evaluation and continuous quality improvement |
Training, supervision and debriefing.
Use continuous improvement processes.
Plan for the response to possible errors.
|
References
- Vaccine Storage and Handling Guidelines (PDF, Ontario Ministry of Health)
- How to Vaccinate: Modern Practices for Vaccine Administration (Immunize Canada)
- ISMP Canada Safety Bulletin: Opportunities to Improve COVID-19 Vaccine Labels
- ISMP Canada Safety Bulletin: Updated Analysis and Shared Learning from COVID-19 Vaccine Errors
- ISMP Canada Safety Bulletin: Preventing Errors with COVID-19 Vaccines: Learning from Vaccine Incidents
- ISMP Canada Safety Bulletin: Pediatric Medication Errors in the Community: A Multi-Incident Analysis includes a sidebar: Preventing Pediatric COVID-19 Vaccine Errors at Mass Vaccination Sites
- Vaccine Administration: Preventing Vaccine Administration Errors (PDF, U.S. Centers for Disease Control and Prevention)
- Recommendations for Global Implementation of Safe COVID-19 Immunization Practices (PDF, International Medication Safety Network initiative: COVID-19 Vaccine Safety Interest Group)
This document was prepared in 2023 by the Ontario Ministry of Health, the Public Health Agency of Canada and the Institute for Safe Medication Practices Canada with input from the Canadian Immunization Committee, and was updated by PHAC in July 2026.
What to do after an error or deviation is detected
If a vaccine administration error or deviation is found, health care providers should:
- inform the client of the vaccine administration error or deviation as soon as possible
- explain any implications or recommendations for future doses, possibility of local or systemic reactions and impact on the effectiveness of the vaccine (if applicable and as known)
- consider culture, age, cognitive ability, language spoken and other diversity factors when communicating with the client
- if the client is a child, inform the parents or guardians and the child as appropriate
- document the error or deviation in the client's medical record
- report all errors, deviations or near-miss incidents in accordance with the reporting processes of the office practice, institutional medication error policy, professional body or province or territory
- you may also report errors or deviations to the Canadian Medication Incident Reporting and Prevention System (CMIRPS)
- errors may also be reportable to your provincial or territorial immunization program according to their guidance and processes
- complete the jurisdiction's Adverse Event Following Immunization (AEFI) form and submit it to the local public health authority if a vaccine administration error or deviation results in an AEFI.
- find information on AEFI reporting on the AEFI page
- determine how the vaccine administration error or deviation occurred and implement strategies to prevent it from happening again
The purpose of the remaining sections of this document are to assist in the management of specific errors and deviations that may arise.
Important context regarding guidance
There is limited evidence to guide the management of errors or deviations. The manufacturer may have information that can assist with making decisions regarding error and deviation management, and public health officials are available to assist with management advice regarding vaccine errors or deviations.
This document provides guidance only. Note that local, provincial and territorial protocols may differ from this guidance document. Clinical judgement 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.
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. The term "invalid" in this document refers to a dose that may not result in the desired effects and is recommended to be repeated. However, as noted above, clinical judgement is required to determine whether a dose is invalid and should be repeated. Factors that can be considered in making clinical judgements about whether to consider a dose invalid and whether to repeat the dose include:
- How substantially different was the error or deviation from what is recommended?
- 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, including immunocompromising conditions)?
- Has the client had any significant adverse events after previous doses?
- If the client experienced a significant local or systemic reaction following a previous COVID-19 vaccination and a repeat dose is being considered, base your decision to offer a repeat dose on a case-by-case basis in consultation with an allergist, immunologist or another appropriate physician.
Once a decision is made that a dose is "invalid" and is recommended to be repeated, guidance on how to repeat the dose is provided in the following sections:
- Recommendations for repeating a dose in the primary series because it may be too low or not sufficiently potent
- Recommendations for repeating a dose because it may be too low or not sufficiently potent in those who previously completed a primary series
- Recommendations for repeating a dose because the interval is too short
Recommendations for repeating a dose in the primary series because it may be too low or not sufficiently potent
The following guidance relates to recommendations for repeating a dose in the primary series that is considered invalid due to the potential for an inadequate response because of too small a dose, over-dilution, or storage or handling deviations that could impact potency.
- If the error is discovered in time to repeat the dose on the same clinic day, offer a repeat dose on the same clinic day at a separate anatomic injection site (e.g., different limb whenever possible), preferably using the same product.
- In most circumstances, the full age-appropriate dose should be repeated. The only exception is if 50 mcg of Moderna Spikevax is indicated and only 25 mcg of Moderna Spikevax was administered, in which case the additional 25 mcg of Moderna Spikevax can be administered.
- If the dose cannot be repeated on the same clinic day, and it is the:
- first dose or only dose in the primary series, repeat with a full age-appropriate dose as soon as possible
- this is to support the development of an immune response as soon as possible in someone with no prior vaccinations
- second, third or fourth dose in the primary series (if applicable), repeat with a full age-appropriate dose at 4 to 8 weeks from the invalid dose
- this waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events
- first dose or only dose in the primary series, repeat with a full age-appropriate dose as soon as possible
- Inform the client of the potential for local and systemic adverse events from the repeat dose.
- If the client requires a subsequent dose, give it with a recommended age-appropriate dosage and product and follow the recommended interval from the repeat dose.
Recommendations for repeating a dose because it may be too low or not sufficiently potent in those who previously completed a primary series
The following guidance relates to recommendations for repeating a dose in those who have previously completed a primary series when the dose is considered invalid due to the potential for an inadequate response because of too small a dose, over-dilution, or storage or handling deviations that could impact potency.
- If the error is discovered in time to repeat the dose on the same clinic day, offer a repeat dose on the same clinic day at a separate anatomic injection site (e.g., different limb whenever possible), preferably using the same product.
- In most circumstances, the full age-appropriate dose should be repeated. The only exception is if 50 mcg of Moderna Spikevax is indicated and only 25 mcg of Moderna Spikevax was administered, in which case the additional 25 mcg of Moderna Spikevax can be administered.
- If the dose cannot be repeated on the same clinic day, repeat with a full age-appropriate dose at 8 weeks from the invalid dose.
- This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events.
- Inform the client of the potential for local and systemic adverse events from the repeat dose.
- If the client requires a subsequent dose in the future, give it with a recommended age-appropriate dosage and product and follow the recommended interval from the repeat dose.
Recommendations for repeating a dose because the interval is too short
The following guidance relates to recommendations for repeating a dose that is considered invalid because the interval is too short between vaccine doses.
- If the invalid dose is in the primary series, repeat at 8 weeks from the invalid dose for those who are not immunocompromised and at 4 to 8 weeks from the invalid dose for those who are moderately to severely immunocompromised.
- If the invalid dose is a dose in those who have previously completed their primary series, repeat at 8 weeks from the invalid dose.
- This waiting period is to allow some immune response to the invalid dose to develop and to minimize the risk of adverse events.
- Inform the client of the potential for local and systemic adverse events from the repeat dose.
- If the client requires a subsequent dose, give it with a recommended age-appropriate dosage and product and follow the recommended interval from the repeat dose.
Refer to the COVID-19 chapter of the Canadian Immunization Guide for recommended intervals for the primary series or for those who previously completed a primary series.
Serologic testing
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 department 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 and recommended actions
Site or route errors
Recommended site and route
COVID-19 vaccines should be administered intramuscularly. The anterolateral thigh (vastus lateralis) is the preferred site for children less than 1 year 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 toddlers and older children 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). See Route, site and technique for vaccine administration: Canadian Immunization Guide for additional information.
Guiding principles for site or route errors
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
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
Recommended dosages by age
Refer to Table 1 in the COVID-19 chapter of the Canadian Immunization guide.
Guiding principle for too high a dose
Too high a dose can result from:
- using the wrong dosage according to the client's age
- not adding diluent or not adding enough diluent to a product that requires dilution.
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.
Dose, product or schedule error based on age
There are some preparations of COVID-19 vaccines that are authorized for use in Canada but are not available or may only be available through the private market. Available products may vary by jurisdiction. All authorized COVID-19 vaccines are listed in the Contents of immunizing agents authorized for use in Canada chapter of the Canadian Immunization Guide.
Select the age group of your client:
Children 6 months to under 5 years of age
Recommendations for children 6 months to less than 5 years of age who are previously unvaccinated
See the Canadian Immunization Guide for recommendations for who should receive COVID-19 vaccines.
The recommended schedule for those who are NOT moderately or severely immunocompromised is:
- 2 doses of Moderna Spikevax LP.8.1-containing vaccine (25 mcg), 8 weeks apart
- 3 doses of Pfizer-BioNtech Comirnaty LP.8.1-containing vaccine (3 mcg), with 8 weeks between doses
For those who are moderately to severely immunocompromised the schedule is:
- 3 doses of Moderna Spikevax LP.8.1 vaccine (25 mcg), with 4 to 8 weeks between doses
Pfizer-BioNTech (3 mcg) is not the preferred product for children 6 months to less than 5 years of age who are moderately to severely immunocompromised because of the number of doses (4) in this primary series.
Note that if a primary series consisted of at least one dose of a Pfizer-BioNtech COVID-19 vaccine, the total number of doses should be as per the Pfizer-BioNTech schedule for children 6 months to less than 5 years of age (3 doses for non-immunocompromised and 4 doses for those who are moderately to severely immunocompromised). Refer to the COVID-19 chapter of the Canadian Immunization Guide for recommendations for these children 6 month to less than 5 years of age.
Recommendations for children 6 months to less than 5 years of age who started but did not complete the primary series
If the child started but did not complete the primary series, it should be completed with either Moderna Spikevax LP.8.1 or Pfizer-BioNTech Comirnaty LP.8.1 vaccine so that in total they receive the number of doses indicated above (including both previous COVID-19 vaccines and the LP.8.1 COVID-19 vaccines).
If a child transitions from 4 to 5 years of age during the primary series, consult the COVID-19 chapter of the Canadian Immunization Guide in the section for the primary series for children 6 months to under 5 years of age.
Recommendations for children 6 months to less than 5 years of age who previously completed a primary series
See the COVID-19 chapter of the Canadian Immunization Guide for recommendations for who should receive COVID-19 vaccines.
The schedule for most previously vaccinated individuals is one dose per year, with two doses per year for some higher risk individuals
Guiding principles for managing too low of a dosage given to children 6 months to under 5 years of age
Too low a dose could result from the following:
- using the wrong dosage according to the client's age
- a product requiring dilution was over diluted
- a product not requiring dilution was diluted
- only diluent was administered
- leakage of vaccine during administration
- equipment failure
- the client pulled away while the dose was being injected
The dosages of COVID-19 vaccine vary by product and age. See the COVID-19 chapter of the Canadian Immunization Guide.
Any dose that is known or suspected to be below the age-appropriate dosage should be considered invalid and repeated as per the Recommendations for repeating a dose in the primary series because it may be too low or not sufficiently potent and Recommendations for repeating a dose because it may be too low or not sufficiently potent in those who previously completed a primary series.
See the section on important context regarding guidance when considering a dose invalid.
Guiding principle for receiving COVID-19 vaccines from previous seasons
Note that all non-LP.8.1 mRNA vaccines should no longer be available.
If a non-LP.8.1 mRNA vaccine was given in error, consider the dose valid and administer the next dose(s) as per usual based on the COVID-19 chapter of the Canadian immunization Guide.
Individuals 5 years of age and older
Recommendations for individuals 5 years of age and older who are previously unvaccinated
See the Canadian Immunization Guide for recommendations for who should receive COVID-19 vaccines.
The recommended schedule for those who are NOT moderately to severely immunocompromised is:
- Individuals 5 to 11 years of age:
- 1 dose of either Moderna Spikevax LP.8.1 vaccine (25 mcg) or Pfizer-BioNTech Comirnaty LP.8.1 (10 mcg)
- Individuals 12 years of age and older:
- 1 dose of either Moderna Spikevax LP.8.1 vaccine (50mcg), Pfizer-BioNTech Comirnaty LP.8.1 vaccine (30mcg), or Novavax Nuvaxovid JN.1 vaccine (5 mcg)
- for Novavax Nuvaxovid, 2 doses of vaccine are authorized as the primary series for those 12 years of age and over; however, for those in this age group who are not immunocompromised, 1 dose may be used in the primary series
The recommended schedule for those who are moderately to severely immunocompromised is:
- Individuals 5 years to 11 years of age:
- 2 doses of either Moderna Spikevax LP.8.1 vaccine (25 mcg) or Pfizer-BioNTech Comirnaty (10 mcg) should be given, and an additional dose (for a total of 3 doses) may be given, with 4 to 8 weeks between doses
- Individuals 12 years of age and older:
- 2 doses of either Moderna Spikevax LP.8.1 vaccine (50mcg), Pfizer-BioNTech Comirnaty LP.8.1 vaccine (30mg), or Novavax Nuvaxovid JN.1 vaccine (5 mcg) should be given, and an additional dose (for a total of 3 doses) may be given, with 4 to 8 weeks between doses
Note: new recipients of haematopoietic stem cell transplantation (HSCT) or chimeric antigen receptor (CAR) T-cell therapy are considered immunologically naïve and should be vaccinated with 3 doses beginning at 3 to 6 months post-HSCT/CAR T-cell therapy, regardless of vaccination or infection history prior to transplant/therapy, with 4 to 8 weeks between doses.
If a primary series for those who are moderately to severely immunocompromised was started with a previous season's COVID-19 vaccine, it should be completed with the vaccines noted above so that in total they receive the number of doses indicated above (including both previous season's and current season's COVID-19 vaccines).
If a child transitions from 4 to 5 years of age during the primary series, consult the COVID-19 chapter of the Canadian Immunization Guide in the section for the primary series for children 6 months to under 5 years of age.
Recommendations for individuals 5 years of age and older who previously completed a primary series
See the Canadian Immunization Guide for recommendations for who should receive COVID-19 vaccines.
The schedule for most previously vaccinated individuals is one dose per year, with two doses per year for some higher risk individuals.
Guiding principles for managing too low of a dosage given to individuals 5 years of age and over
Too low a dose could result from the following:
- using the wrong dosage according to the client's age
- a product not requiring dilution was diluted
- only diluent was administered
- leakage of vaccine during administration
- equipment failure
- the client pulled away while the dose was being injected
The dosages of COVID-19 vaccine vary by product and age. See the COVID-19 chapter of the Canadian Immunization Guide.
Any dose that is known or suspected to be below the age-appropriate dosage should be considered invalid and repeated as per the Recommendations for repeating a dose in the primary series because it may be too low or not sufficiently potent and Recommendations for repeating a dose because it may be too low or not sufficiently potent in those who previously completed a primary series.
See the section on important context regarding guidance when considering a dose invalid.
Guiding principle for receiving COVID-19 vaccines from previous seasons
Note that all non-LP.8.1 mRNA and non-JN.1 Novavax Nuvaxovid vaccines should no longer be available.
If a non-LP.8.1 mRNA vaccine or non-JN.1 Novavax Nuvaxovid vaccine was given in error, consider the dose valid and administer the next dose(s) as per usual based on the COVID-19 chapter of the Canadian immunization Guide.
Concurrent administration
Recommendations for concurrent administration
NACI recommends that for individuals 6 months 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).
Mixing more than 1 vaccine in the same syringe
Recommendations
COVID-19 vaccines should never be mixed in the same syringe as other vaccines, as it is possible that the components of one vaccine may have a detrimental effect on the other(s).
Guiding principle for different vaccines combined in 1 syringe for single administration
The manufacturer should be consulted to determine if they have any particular information on the mixing of vaccines (including the particular vaccines that were mixed), recognizing that this information may not be available. In general, if 2 or more vaccines were administered in the same syringe, consider all vaccine doses as invalid and all vaccines mixed together should be repeated.
For an invalid COVID-19 vaccine dose, the vaccine should be repeated as per the Recommendations for repeating a dose in the primary series because it may be too low or not sufficiently potent and Recommendations for repeating a dose because it may be too low or not sufficiently potent in those who previously completed a primary series. The repeat COVID-19 vaccine dose can be given concurrently at the same visit with the other vaccine(s) that require repeating (i.e., the other vaccines that were erroneously mixed in the same syringe). The repeat vaccines should be administered using separate injection sites and separate injection equipment (i.e., separate needles and syringes).
See the section on important context regarding guidance when considering a dose invalid.
Interval errors
Recommended intervals between COVID-19 vaccine doses, or SARS-CoV-2 infection and COVID-19 vaccine doses
Recommended intervals between COVID-19 vaccine doses, or between test-confirmed SARS-CoV-2 infection and COVID-19 vaccination for those who are not immunocompromised and those who are moderately to severely immunocompromised are provided in:
- Table 1 of the COVID-19 chapter in the Canadian Immunization Guide
- the section of the COVID-19 chapter in the Canadian Immunization Guide on the schedule for those previously vaccinated
- the section of the COVID-19 chapter in the Canadian Immunization Guide on individuals previously infected with SARS-CoV-2
Guiding principle for COVID-19 vaccine doses given longer than the recommended interval
Recommended intervals are attempting to balance achieving a good immune response and the period at risk for infection and/or severe disease between COVID-19 vaccine doses. All doses given beyond the recommended interval are considered valid, whether for the primary series that requires more than 1 dose or for the doses in those who have previously completed a primary series, including for moderately to severely immunocompromised people.
Guiding principle for COVID-19 vaccine doses given earlier than the recommended interval
Doses given too close together may not result in an optimal immune response because of:
- less than recommended time to allow for the immune response to mature between doses
- antibodies produced to the early dose may interfere with the antibody response to the later dose
Primary series: When the primary series consist of more than 1 dose, COVID-19 vaccine doses given less than 21 days apart (for both Pfizer-BioNTech Comirnaty or Moderna Spikevax) are considered invalid and should be repeated as per the Recommendations for repeating a dose because the interval is too short.
See the section on important context regarding guidance when considering a dose invalid.
Doses in those who previously completed a primary series: COVID-19 vaccine doses given less than 8 weeks apart in those who previously completed a primary series are considered invalid and should be repeated as per the Recommendations for repeating a dose because the interval is too short.
See the section on important context regarding guidance when considering a dose invalid.
Vaccine doses given at any interval after SARS-CoV-2 infection are considered valid and do not need to be repeated.
Storage and handling errors
Recommendations regarding storage and handling
Storage and handling recommendations can be found in the product monographs for Pfizer-BioNTech Comirnaty (PDF) and Moderna Spikevax (PDF).
Guiding principles for storage and handling errors of products that have been administered
Storage and handling errors or deviations can include:
- Excursions beyond the recommended time or temperature based on the product monograph.
- Incorrect diluent type (i.e., a diluent other than the 0.9% Sodium Chloride Injection, USP recommended for Pfizer-BioNtech Comirnaty LP.8.1 [3 mcg] for children 6 months to less than 5 years).
Management of storage and handling errors requires individual consideration based on the particular circumstances, in consultation with the manufacturer and based on clinical judgment. Local public health officials can also be contacted for assistance and should be notified of any temperature excursions.
In consulting with the manufacturer, inquire if they have any specific information related to the particular storage and handling error or deviation involving the specific product or lot number or more general information that may help to inform decisions regarding the error or deviation. In addition to information from the manufacturer, and as noted in the section on important context regarding guidance, 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 relative to the recommended storage and handling conditions)?
- 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, including immunocompromising conditions)?
- Has the client had any significant adverse events after previous doses?
If a dose is deemed to be invalid, it should be repeated as per the Recommendations for repeating a dose in the primary series that may be too low or not sufficiently potent and Recommendations for repeating a dose that may be too low or not sufficiently potent in those who previously completed a primary series. For the second, third or fourth doses in the primary series (if applicable), the section for the primary series suggests an interval of 4 to 8 weeks to repeat the invalid dose:
- the longer interval of up to 8 weeks to repeat the invalid dose can be considered if there was only a relatively small deviation in time or temperature above cold chain requirements
- the shorter interval of down to 4 weeks can be considered to repeat the invalid dose if there was a relatively large deviation in time or temperature above cold chain requirements
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 considered valid.
Related links
- COVID-19 vaccine: Canadian Immunization Guide
- National Advisory Committee on Immunization COVID-19 statements
- COVID-19 for health professionals: Vaccines
- Vaccines for COVID-19
- Interim clinical considerations for use of COVID-19 vaccines currently authorized in the U.S. (Centers for Disease Control and Prevention)
- COVID-19 vaccination programme: information for healthcare practitioners