COVID-19 vaccines: Canadian Immunization Guide

For health professionals

Last partial content update: October 2026

This chapter has been updated with the following statement from the National Advisory Committee on Immunization (NACI):

• June 2026: Guidance on the use of COVID-19 vaccines starting fall 2026 (PDF)
• Summary of guidance on the use of COVID-19 vaccines starting fall 2026

This chapter was also revised with information on updated COVID-19 vaccine products for use beginning fall 2026.

This information is captured in the table of updates.

On this page

• Epidemiology
• Preparations authorized for use in Canada
• Immunogenicity, efficacy and effectiveness
• Recommendations for use
  • Schedule for the primary dose/series
    • Table 1. Immunization schedule for previously unvaccinated individuals by age
  • Schedule for those previously vaccinated
• Vaccination of specific populations
  • Pregnancy and breastfeeding
  • Individuals previously infected with SARS-CoV-2
  • Immunocompromised persons
  • Travellers
  • Persons new to Canada
• Serologic testing
• Administration practices
  • Dose and route of administration of available products
  • Interchangeability of vaccines
  • Concurrent administration with other vaccines
  • Pre-vaccination counselling
  • Post-vaccination counselling
• Storage requirements
• Safety and adverse events
  • Very common and common adverse events
  • Uncommon, rare and very rare adverse events
  • Guidance on reporting adverse events following immunization (AEFI)
  • Contraindications and precautions
• Other considerations
  • Tuberculin skin testing (TST) and interferon gamma release assay (IGRA)
• Chapter revision process
• Acknowledgments
• Selected references

Please note: The Public Health Agency of Canada (PHAC) recognizes that not all people giving birth or breastfeeding will identify as women or mothers. The writing in this chapter uses a gender additive approach where the term 'woman' is used alongside gender neutral language. This is intended to demonstrate a commitment to redress the historic exclusion of trans and non-binary people, whilst avoiding the risk of marginalizing or erasing the experience of women within the health care environment. However, in line with best practice, it is recognized that when discussing or caring for individuals in a one-on-one capacity, language and documentation should reflect the gender identity of the individual.

Epidemiology

Disease description

Infectious agent

COVID-19 is caused by the SARS-CoV-2 virus.

Transmission

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

Variants of concern

Genetic mutations in the SARS-CoV-2 virus have led to the designation of variants of concern (VOCs). Such mutations may lead to changes in transmissibility, severity of disease or the level of protection offered by vaccines or previous infection. Since late December 2021, Omicron has been the predominantly circulating strain.

Information on the COVID-19 variants in Canada is available in the Canadian respiratory virus surveillance report: COVID-19.

Risk factors

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

There is a spectrum of COVID-19 disease severity, ranging from asymptomatic to mild, moderate, severe and fatal disease. Severe disease more often occurs in those with increasing age and those with underlying medical conditions, with the risk increasing with the number of underlying conditions. A list of underlying medical conditions associated with more severe disease from COVID-19 can be found in COVID-19: For health professionals. The risk of severe illness from COVID-19 follows an age-related gradient in older adults. Adults 80 years of age and older are at highest risk, and the risk is also higher among those who are more frail at any age.

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

Spectrum of clinical illness and disease characteristics

The median incubation period (the time from exposure to symptom onset) is 2 to 4 days. The incubation period can range from 2 to 14 days.

Clinical presentation of COVID-19 varies from asymptomatic to severe and fatal disease.

More information on the spectrum of clinical illness is available on the PHAC webpage for COVID-19: For health professionals.

While most children and adolescents with COVID-19 have mild or no symptoms, some do experience severe disease. However, fewer severe outcomes of COVID-19 are reported in children and adolescents compared to older age groups.

People infected with SARS-CoV-2 are at risk of post COVID-19 condition (PCC), a condition in which symptoms persist for more than 8 weeks and are present 12 or more weeks following acute infection with SARS-CoV-2 and cannot be explained by an alternate diagnosis. Refer to Effectiveness of vaccination against post-COVID-19 condition.

Disease incidence

Global

The WHO COVID-19 dashboard provides an overview of reported data on SARS-CoV-2 viral activity and the burden of COVID-19 on the human population over the past seven to 28 days from the last reporting date.

National

At the national level, Canadian SARS-CoV-2 surveillance information is available from the Respiratory Virus Detection Surveillance System (RVDSS).

The seasonality of SARS-CoV-2 has not been established. SARS-CoV-2 has been circulating year-round, with periodic surges in disease activity. In recent surveillance periods (i.e., 2022-23, 2023-24 and 2024-25), COVID-19 disease activity has started to increase in the late spring or late summer and has remained higher from September to January, compared to other time periods.

Back to table of contents at top of page

Preparations authorized for use in Canada

Older versions of the COVID-19 vaccine are no longer authorized for use and no longer available. 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 Contents of immunizing agents authorized for use in Canada in Part 1.

mRNA vaccines

• SPIKEVAX^®, (dosages of 50 mcg or 25 mcg of mRNA encoding for the spike protein of SARS-CoV-2 Omicron XFG variant), Moderna Biopharma Canada Corp.
  • Authorized for use in those 12 years of age and older (50 mcg) and in children 6 months to 11 years of age (25 mcg)
• mNEXSPIKE™, (single dose prefilled syringe to administer a dosage of 10 mcg), Moderna Biopharma Canada Corp.
  • mNEXSPIKE (mRNA-1283) is an mRNA vaccine that is a next-generation version of Moderna Spikevax (mRNA-1273). Unlike Moderna SPIKEVAX, which encodes for the whole spike protein, mNEXSPIKE encodes for only part of the SARS-CoV-2 spike protein (the N-terminal domain [NTD] and receptor-binding domains [RBD]) of SARS-CoV-2 Omicron XFG variant.
  • Authorized for use in previously vaccinated adults 18 years of age and older.
  • Note this vaccine is not yet available in Canada.
• COMIRNATY^®, (dosages of 30 mcg, 10 mcg or 3 mcg of mRNA encoding for the spike protein of the SARS-CoV-2 Omicron XFG variant), Pfizer and BioNTech Manufacturing GmbH
  • Authorized for use in those 12 years of age and older (30 mcg), children 5 to 11 years of age (10 mcg), and children 6 months of age to less than 5 years of age (3 mcg).

mRNA COVID-19 vaccines contain mRNA that codes for either the full SARS-CoV-2 spike protein or specific antigenic domains of the spike protein. The mRNA sequence is updated periodically according to recommendations from expert advisory bodies such as the World Health Organization's Technical Advisory Group on COVID-19 Vaccine Composition (WHO TAG-CO-VAC). A lipid nanoparticle formulation delivers the mRNA into the recipient's cells. Once inside the cytoplasm of a cell, the mRNA provides instructions to the cell's protein production machinery to produce the antigen that becomes anchored on the cell's external surface. The mRNA does not enter the nucleus of the cell and does not interact with, or alter, human DNA. The immune system is engaged by both the transmembrane spike protein and immune receptors carrying spike antigens to induce humoral and cellular immune responses. The mRNA, lipid nanoparticle, and spike protein are degraded or excreted within days to weeks from time of immunization.

Protein subunit vaccine

• NUVAXOVID™ (dosage of 5 mcg of recombinant spike protein of the SARS-CoV-2 Omicron XFG variant co-formulated with Matrix M) is authorized for those 12 years of age and over.

The protein subunit vaccine consists of a purified full-length SARS-CoV-2 recombinant spike protein nanoparticle co-formulated with the adjuvant Matrix-M. Matrix-M is a novel saponin-based adjuvant that facilitates activation of the cells of the innate immune system, which enhances the magnitude of the spike protein-specific immune response.

Back to table of contents at top of page

Immunogenicity, efficacy and effectiveness

Immunogenicity

All COVID-19 vaccines induce humoral immune responses, including binding and neutralizing antibody responses, and have been shown to produce cellular immune responses in adult populations. The immune responses may vary depending on the product used, number of doses, interval between the doses (longer intervals result in higher antibody titres), the strains against which the immune response is assessed and how immunologically similar the strain is to the vaccine strain, the age and underlying medical conditions of the vaccine recipient (antibody titres may be lower in older adults and those who are immunocompromised due to disease or medication) and the recipient's prior infection and vaccination history, including the time since last COVID-19 vaccination or SARS-CoV-2 infection. Antibody titres decrease over time since vaccination, although memory responses that can be boosted with vaccination or infection persist.

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

Efficacy and effectiveness

Efficacy and effectiveness of COVID-19 vaccines tends to be lowest against infection, higher against symptomatic disease and highest against severe disease.

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

Studies have demonstrated efficacy against symptomatic disease of original monovalent vaccines in children.

Vaccine protection decreases over time, particularly against infection and symptomatic disease, and to a lesser extent against severe disease. Subsequent doses in those previously vaccinated increase protection, particularly against severe disease, that may have waned over time.

Many people have had SARS-CoV-2 infections. Protection against future infections is higher in those with previous SARS-CoV-2 infection and vaccination (hybrid immunity) than in those who have only been vaccinated or only been infected. Vaccine effectiveness studies for vaccines that are updated annually have demonstrated that vaccination increases protection against symptomatic disease, hospitalization and critical illness, even in populations with immunity from high rates of past infections and/or vaccinations.

Vaccination may offer protection against transmission as it may reduce viral load and duration of infection.

Effectiveness of vaccination against post-COVID-19 condition

To the extent that vaccination prevents infection, it also prevents PCC. As well, people who are vaccinated with two doses and then become infected likely have additional protection against PCC compared to those who are not vaccinated. The impact of COVID-19 vaccinations on PCC continues to be monitored through emerging literature.

Back to table of contents at top of page

Recommendations for use

COVID-19 vaccination is recommended for individuals at increased risk of SARS-CoV-2 exposure or severe COVID-19 disease as follows:

• All adults 65 years of age or older
• Those 6 months of age and older who are:
  • residents of long-term care homes and other congregate living settings
  • individuals with underlying medical conditions that place them at higher risk of severe COVID-19, including children^{Footnote 1} with complex health needs
  • pregnant women and pregnant individuals
  • individuals in or from First Nations, Métis and Inuit communities^{Footnote 2}
  • members of racialized and other equity-denied communities^{Footnote 3}
  • health care workers and other care providers in facilities and community settings^{Footnote 4}

All individuals 6 months of age and over not in the preceding list may receive the COVID-19 vaccine. Risks of acquiring COVID-19 are higher in some settings and risks from SARS-CoV-2 infection are higher in some individuals. Individuals may choose to receive the vaccine based on individual COVID-19 risk assessment or preference.

Some individuals at increased risk of severe illness should receive two doses of COVID-19 vaccine per year, at a minimum interval of 3 months from the previous dose:

• Adults 80 years of age and older
• Residents of long-term care homes, as well as residents of other congregate living settings for seniors
• Individuals 6 months of age and older who are moderately to severely immunocompromised (due to an underlying condition or treatment)
• Adults 65 to 79 years of age with underlying medical conditions that place them at higher risk of severe COVID-19

Adults 65 to 79 years of age who are not in the preceding list may receive a second dose of COVID-19 vaccine per year, at a minimum interval of 3 months from the previous dose.

Schedule for the primary dose/series

Children 6 months to under 5 years of age

An mRNA vaccine (Moderna Spikevax or if available, Pfizer-BioNTech Comirnaty) can be used for any child 6 months to less than 5 years who is starting or completing their primary series. Pfizer-BioNTech Comirnaty may not be available for children less than 5 years of age.

Using Moderna Spikevax, 2 doses with an 8-week interval between doses is the recommended schedule for those 6 months to less than 5 years of age who are not moderately to severely immunocompromised. An additional dose is recommended for individuals who are moderately to severely immunocompromised, with an interval of 4 to 8 weeks between each dose (see Table 1 for schedules and dosages).

If Pfizer-BioNTech Comirnaty is available for children 6 months to less than 5 years, 3 doses, with an 8-week interval between doses, is the recommended schedule for those who are not moderately to severely immunocompromised. Because of the requirement for 4 doses, Pfizer-BioNTech is not the preferred product for children 6 months to less than 5 years who are moderately to severely immunocompromised. Any primary series for children 6 months to less than 5 years that consisted of at least one dose of Comirnaty should follow the schedule for Comirnaty, even if Spikevax is being used as part of the schedule.

The 8-week interval is longer than the authorized interval and is recommended as a better immune response has been associated with a longer interval between doses. For those who are moderately to severely immunocompromised, the 4- to 8-week interval between doses needs to balance a potentially better immune response with longer intervals with the need for earlier protection due to risk of exposure from circulating SARS-CoV-2 and the risk of severe COVID-19 disease.

Those who are moderately to severely immunocompromised are recommended to receive an additional dose in the primary series to help improve the immune response and vaccine effectiveness in this group. Those who are moderately to severely immunocompromised respond less well to COVID-19 vaccines and are at higher risk for severe illness.

For children who started a primary series at less than 5 years of age and turn 5 years of age before completing the primary series, see section below entitled Children who started but did not complete a primary series at less than 5 years of age and are now between 5 and 11 years of age.

Individuals 5 years of age and over

For mRNA vaccines, 1 dose of vaccine is the recommended schedule for those 5 years of age and older, not previously vaccinated, as per the authorized schedule in the product monograph. Both Moderna Spikevax and Pfizer-BioNTech Comirnaty can be used for those 5 years of age and over. For 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, 1 dose may be used for those not previously vaccinated.

For individuals 5 years of age and over who are moderately to severely immunocompromised, 2 doses of COVID-19 vaccine are recommended for the primary series and a third dose may be offered based on clinical discretion, with an interval of 4 to 8 weeks between the doses. Either mRNA vaccine (Moderna Spikevax or Pfizer-BioNTech Comirnaty) may be used, or depending on age and availability, Nuvaxovid vaccine may be used (see Table 1 for schedules and dosages). Recipients of hematopoietic stem cell transplantation (HSCT) or chimeric antigen receptor (CAR) T cell therapy should receive 3 doses with an interval of 4 to 8 weeks between doses.

Those who are moderately to severely immunocompromised generally respond less well to COVID-19 vaccines and are at higher risk for severe illness. In some cases, a third dose may be recommended based on the clinical discretion of the health care provider. However, new recipients of hematopoietic stem cell transplantation (HSCT) and 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 previous vaccination history.

The 4 to 8-week interval for those who are moderately to severely immunocompromised needs to balance a potentially better immune response with the longer interval with the need for earlier protection due to risk of exposure from circulating SARS-CoV-2 and the risk of severe disease.

For children who started a primary series at less than 5 years of age and turn 5 years of age before completing the primary series, see section below entitled Children who started but did not complete a primary series at less than 5 years of age and are now between 5 and 11 years of age.

There is no preference between mRNA vaccines and protein subunit vaccines for those 12 years of age and over.

Children who started but did not complete a primary series at less than 5 years of age and are now between 5 and 11 years of age

Children who started the primary series at less than 5 years of age and turn 5 years of age before completing the series, can use either the Moderna Spikevax or Pfizer-BioNTech Comirnaty mRNA vaccines to complete the primary series as follows:

• Not moderately to severely immunocompromised: 1 dose of vaccine
• Moderately to severely immunocompromised: so that the total number of COVID-19 doses received is 3 doses for Moderna Spikevax, or 4 doses for a schedule that was started with or included Pfizer-BioNTech Comirnaty.

Schedule for those previously vaccinated

The schedule for most individuals is one dose per year, with two doses per year for some higher risk individuals (see beginning of the section Recommendations for use). The minimum interval between COVID-19 vaccine doses is 3 months. For individuals with test-confirmed SARS-CoV-2 infection, a minimum interval of 3 months can be considered if the person is due for a COVID-19 vaccination.

Recognizing that vaccine protection is higher shortly after vaccination and based on availability from provinces and territories, people may make individual decisions regarding the optimal time for their COVID-19 vaccine dose considering factors such as time since their last COVID-19 vaccine dose or test-confirmed SARS-CoV-2 infection, circulation of SARS-CoV-2 in the community, and upcoming major events such as travel, significant medical procedures or large gatherings.

For ages where both platforms are authorized, either mRNA or the protein subunit vaccines can be used, with no preference between vaccine platforms.

Back to table of contents at top of page

Vaccination of specific populations

Pregnancy and breastfeeding

Compared to non-pregnant persons, SARS-CoV-2 infection in pregnancy is associated with increased risk of hospitalization and admission to an ICU. SARS-CoV-2 infection during pregnancy is also associated with an increased risk of preterm birth, low birth weight and admission to a neonatal intensive care unit (NICU). Vaccination helps to protect the person who is pregnant and vaccination during pregnancy also lowers the risk of hospitalization for their newborn.

Recommendations

Women and individuals who are pregnant or breastfeeding are recommended to be vaccinated as per the Recommendations for use section. COVID-19 vaccines can be given at any stage of pregnancy.

Pregnancy is an indication for an annual dose of COVID-19 vaccine (with availability determined by the provinces and territories).

Either mRNA vaccines or the protein subunit vaccine may be used for pregnant women and pregnant individuals.

Considerations

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

Evidence suggests that COVID-19 mRNA vaccination during pregnancy results in comparable antibody titres to those of non-pregnant women. Maternal IgG from mRNA COVID-19 vaccines transfers across the placenta to the fetus, leading to a significant antibody titre in the neonate. Infants of people who received COVID-19 during pregnancy had a lower risk of hospitalization with COVID-19 compared to infants born to individuals who were unvaccinated. The effect was greater if the dose was given later in the pregnancy. The protection from maternal vaccination against infant hospitalization decreases with time after birth.

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

Individuals previously infected with SARS-CoV-2

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

Recommendations

Vaccination is recommended in those who are previously infected as per the Recommendations for use section.

For those who are previously vaccinated and who test positive for SARS-CoV-2, a minimum of 3 months from test-confirmed infection to COVID-19 vaccination may be considered.

These suggested intervals from infection to COVID-19 vaccination serve as a guide and are based on immunological principles and expert opinion and may change as evidence emerges. Clinical discretion can be applied.

Individuals with a history of multisystem inflammatory syndrome in children or adults (MIS-C or MIS-A) should wait to be vaccinated for at least 90 days from diagnosis or clinical recovery, whichever is longer.

Considerations

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

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

When considering the suggested intervals outlined above, risk factors for exposure (e.g., local epidemiology, living settings) and severe disease should be considered.

Immunocompromised persons

Individuals with immunocompromising conditions, including those receiving immunosuppressive therapy, are at increased risk for prolonged infection, serious complications from SARS-CoV-2 infection as well as reduced immune responses to vaccination and reduced vaccine effectiveness. Additional doses may improve the immune response and effectiveness.

Recommendations

People who are moderately to severely immunocompromised are recommended to be vaccinated as per the Recommendations for use section. They are included in the group of people for whom two doses of COVID-19 vaccine are recommended per year.

For those who are moderately to severely immunocompromised, the primary series of updated COVID-19 vaccines is as follows, with an interval of 4 to 8 weeks between doses:

• For those 6 months to under 5 years of age: 3 doses of Moderna Spikevax. Due to the number of doses required (i.e., 4 doses), Pfizer-BioNTech Comirnaty is not the preferred product for children 6 months to less than 5 years of age who are moderately to severely immunocompromised.
• For those 5 years of age and over: 2 doses of any available age-appropriate vaccine are recommended and a third dose may be offered for those who are moderately to severely immunocompromised individuals. The third dose should be offered for new recipients of hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor (CAR) T cell therapy.

Healthcare providers can use clinical discretion to determine the potential benefit of a third dose for those 5 years of age and over who are moderately to severely immunocompromised. However, new recipients of hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor (CAR) T cell therapy should be vaccinated with 3 doses beginning at 3 to 6 months post-HSCT/CAR T-cell therapy, regardless of previous vaccination history. Please refer to Immunization of immunocompromised persons in Part 3 for specific immunization recommendations for these populations.

Either mRNA or protein subunit vaccines may be used for people who are immunocompromised.

Considerations

Immunocompromised individuals, including those receiving immunosuppressive therapy, are at increased risk for prolonged infection and serious complications from SARS-CoV-2 infection. Numerous studies have shown that immunogenicity is substantially decreased in some immunocompromised individuals. Observational studies in adults with complete 1 or 2 dose series, show lower vaccine effectiveness against SARS-CoV-2 infection and COVID-19 disease in immunocompromised adults when compared to the general population. Additional doses are recommended to improve the immune response and vaccine effectiveness. Some individuals may be unable to mount a sufficient response even with additional doses.

In considering the 4 to 8-week interval between vaccine doses in the primary series, a longer interval is likely to result in a better immune response. However, moderately to severely immunocompromised individuals may remain susceptible during the primary series before the next dose is administered; therefore, the risk of exposure (including local transmission of SARS-CoV-2) and risk of severe disease (e.g., underlying high risk medical condition) should be taken into account when considering the intervals in a primary series. For adolescents and young adults, it should also be noted that the risk of myocarditis/pericarditis was lower with longer intervals between doses in the primary series.

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

Moderately to severely immunocompromised includes individuals with the following conditions:

• Immunocompromised due to solid tumour or hematologic malignancies or treatments for these conditions
• Solid-organ transplant and taking immunosuppressive therapy
• Hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppression therapy)
• Immunocompromise due to chimeric antigen receptor (CAR) T cell therapy targeting lymphocytes
• Moderate to severe primary immunodeficiency with associated humoral and/or cell-mediated immunodeficiency or immune dysregulation
• HIV with AIDS-defining illness or TB diagnosis in last 12 months before starting vaccine series, or severe immune compromise with CD4<200 cells/µL or CD4%<15%, or without HIV viral suppression
• Recent treatment with the following categories of immunosuppressive therapies: anti-B cell therapies (monoclonal antibodies targeting CD19, CD20 and CD22), high-dose systemic corticosteroids, alkylating agents, antimetabolites, or tumor-necrosis factor (TNF) inhibitors and other biologic agents that are significantly immunosuppressive
• Chronic kidney disease on dialysis

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

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

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

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

Travellers

Travellers are recommended to be vaccinated as per the Recommendations for use section.

Travellers who are due for COVID-19 vaccinations should optimally complete these at least 2 weeks before departure. Travellers should verify the travel requirements in place at their destination(s). For more information, refer to the Committee to Advise on Tropical Medicine and Travel (CATMAT) Statement on COVID-19 and International Travel.

Persons new to Canada

Persons new to Canada who are planning to live, work or study in Canada should be vaccinated as per the Recommendations for use section.

Back to table of contents at top of page

Serologic testing

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

Back to table of contents at top of page

Administration practices

Dose and route of administration of available products

The following text summarizes authorized vaccine products that are or may be available in Canada, recognizing that some products may not be available or may only be available on the private market and available products may vary by jurisdiction.

Dose

Pfizer-BioNTech Comirnaty COVID-19 vaccines

There are several presentations of Pfizer-BioNTech Comirnaty COVID-19 vaccine authorized for use. Not all of the authorized products listed may be available in Canada.

Pfizer-BioNTech Comirnaty COVID-19 vaccine (30 mcg)

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

Single-dose pre-filled syringe: This preparation is authorized for use in individuals 12 years of age and older.

No dilution is required for any of the above formulations.

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

Pfizer-BioNTech Comirnaty COVID-19 vaccine (10 mcg)

Multidose vial: This presentation has a dark blue vial cap and label and is authorized for use in individuals 5 to 11 years of age.

Single dose vial: This presentation has a light blue vial cap and label and is authorized for use in individuals 5 to 11 years of age.

No dilution is required for either of the above formulations.

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

Pfizer-BioNTech Comirnaty COVID-19 vaccine (3 mcg)

Multidose vial: This presentation has a yellow vial cap and label and is authorized for use in individuals 6 months to 4 years of age.

Dilution is required.

Each dose is 0.3 mL, containing 3 mcg of SARS-CoV-2 spike protein mRNA.

Moderna COVID-19 vaccines

There are several different Moderna COVID-19 vaccines authorized for use. Not all of the authorized products listed may be available in Canada.

Moderna Spikevax COVID-19 vaccines

There are three presentations of Moderna Spikevax authorized for use in Canada:

• For individuals 6 months of age and older;
  • a multidose vial with a 0.10 mg/mL suspension in a 2.5 mL vial with a royal blue vial cap and coral blue label
• For individuals 6 months of age to 11 years of age;
  • a single-dose pre-filled syringe with 25 mcg/0.25 mL with a red label colour
• For individuals 12 years of age and older;
  • a single dose pre-filled syringe with 50 mcg/0.5 mL with a coral blue label colour

No dilution is required for any of the above formulations.

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

Moderna mNexspike COVID-19 vaccine

Pre-filled syringe: This preparation administers a single dose of 10mcg/0.2mL. It authorized for use in previously vaccinated adults 18 years of age and older.

Nuvaxovid COVID-19 vaccine

The product is authorized for 12 years of age and over and formulations include a multi-dose vial and single-dose prefilled syringe. The multidose vial has a blue-coloured cap and contains 5 mcg/0.5 mL in a 2.5 mL multidose vial. Each dose is 0.5 mL, containing 5 mcg SARS-CoV-2 recombinant spike protein.

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

Route of administration

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

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

Interchangeability of vaccines

Any of the Nuvaxovid, Comirnaty and Spikevax COVID-19 vaccines can be used to complete a primary series started with another product, and as subsequent doses in those previously vaccinated. mNexspike can be used as subsequent doses in adults (18 years of age and older) who have been previously vaccinated.

For children who started a primary series at less than 5 years of age and turn 5 years of age before completing the primary series, see section entitled Children who started but did not complete a primary series at less than 5 years of age and are now between 5 and 11 years of age.

Concurrent administration with other vaccines

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

Concurrent administration will reduce barriers to the provision of COVID-19 vaccines with routine childhood immunizations and seasonal influenza immunization. Studies and surveillance activities to assess the safety, immunogenicity and effectiveness of concurrent administration of COVID-19 vaccines with other vaccines have been reassuring to date and are ongoing. Most studies report on the concurrent administration of influenza and COVID-19 vaccines, with the majority of these studies reporting non-inferior immune responses to COVID-19 and influenza after concurrent administration compared to after separate administration.

There are no established safety issues associated with concurrent administration of COVID-19 vaccines with other vaccines.

If more than one type of vaccine is administered at a single visit, they should be administered at different injection sites using separate injection equipment, preferably in different limbs. If the same limb must be used, the injection sites should be separated by at least 2.5 cm (1 inch). COVID-19 vaccines should never be mixed in the same syringe as other vaccines.

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

Pre-vaccination counselling

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

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

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

Refer to Safety and adverse events for further information.

Post-vaccination counselling

Vaccine recipients should be kept under observation for at least 15 minutes after immunization; 30 minutes is a preferred interval when there is a specific concern about a possible vaccine reaction (see Other allergies for additional information).

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

Oral analgesics or antipyretics may be considered for the management of adverse events (e.g., pain or fever, respectively), if they occur after vaccination.

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

Back to table of contents at top of page

Storage requirements

For information on storage, handling and transport of frozen and thawed vaccine vials, refer to the product monograph available through Health Canada's Drug Product Database. Refer to Storage and handling of immunizing agents in Part 1 for additional general information.

Back to table of contents at top of page

Safety and adverse events

Evidence on vaccine safety is available from COVID-19 clinical trials and ongoing national and international COVID-19 vaccine safety monitoring.

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

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

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

Very common and common adverse events

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

Local

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

Systemic

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

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

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

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

Adverse events following updated mRNA COVID-19 vaccines

Evidence on vaccine safety is available from COVID-19 clinical trials and ongoing national and international post-market COVID-19 vaccine safety monitoring. No new adverse events have been identified with the use of updated vaccines, with post-market safety surveillance data suggesting that updated COVID-19 vaccines are tolerated with a similar safety profile as original mRNA COVID-19 vaccines. For mNexspike, post-market safety data are not yet available, and its safety profile is currently informed primarily by clinical trial data.

Uncommon, rare and very rare adverse events

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

Lymphadenopathy

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

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

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

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

• More often after the second dose
• Usually within a week after vaccination
• More often in those 12 to 29 years of age
• More often in males

Symptoms of myocarditis/pericarditis may include:

• chest pain
• shortness of breath
• feeling of a fast or abnormal heartbeat

Analyses of primary series surveillance data in Canada, US and European Nordic countries suggests a higher rate of myocarditis/pericarditis cases reported after vaccination with Moderna Spikevax original (100 mcg) compared to Pfizer-BioNTech Comirnaty original (30 mcg) vaccine especially among 12 to 29 year old males following a second dose of vaccine. Based on data from the original formulation of mRNA COVID-19 vaccines, longer intervals between doses have been noted to result in lower rates of myocarditis/pericarditis. As compared to the original monovalent primary series and booster dose, the risk of myocarditis/pericarditis with updated mRNA vaccine formulations is considerably lower among those 12 to 39 years of age, although evidence specific to mNexspike is limited. While long-term follow-up is ongoing, available data indicate that the majority of individuals who reported myocarditis/pericarditis after mRNA COVID-19 vaccination have responded well to conservative therapy and recover quickly.

Myocarditis/pericarditis after mRNA vaccines is very rare in children less than 12 years of age. No safety signal has been identified in children 6 months to less than 5 years of age.

A further breakdown of the rates of myocarditis/pericarditis after protein subunit vaccines, specifically Nuvaxovid original, by age group (including among adolescents), sex and dose number are not available due to the relatively low number of doses given and reported cases.

Healthcare providers should consider myocarditis/pericarditis in their evaluation if the patient presents with clinically compatible symptoms (e.g., chest pain, shortness of breath, palpitations) after a COVID-19 vaccine.

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

Bell's palsy

Very rare cases of Bell's palsy (weakness or paralysis on one side of the face, which often resolves) have been reported following vaccination with mRNA COVID-19 vaccines (Pfizer-BioNTech Comirnaty original or Moderna Spikevax original) among individuals aged 12 years and older. The Pfizer-BioNTech Comirnaty and Moderna Spikevax product monographs list Bell's palsy as a possible adverse effect. However, available evidence is not currently sufficient to support a causal relationship between the mRNA vaccines and Bell's palsy. A review in the US found no clear or consistent evidence of a safety concern.

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

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

Multisystem inflammatory syndrome in children (MIS-C) is a rare condition which usually occurs 2 to 6 weeks after a child is infected with SARS-CoV-2. MIS-C causes inflammation in various parts of the body, including the heart, lungs, kidneys, brain, skin, eyes and/or gastrointestinal tract. MIS-C is rare and requires hospitalization. Most children recover. Multisystem inflammatory syndrome in adults (MIS-A) is a similar syndrome that very rarely affects adults.

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

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

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

Anaphylaxis is a very rare, severe, life-threatening allergic reaction typically with rapid onset that involves multiple organ systems and can progress rapidly. Symptoms and signs of anaphylaxis may include but are not limited to:

• generalized urticaria
• wheezing
• swelling of the mouth, tongue, and throat
• difficulty breathing
• vomiting
• diarrhea
• hypotension
• decreased level of consciousness, and/or
• shock

Very rare cases of severe immediate allergic reactions (e.g., anaphylaxis) have been reported following vaccination with mRNA and protein subunit COVID-19 vaccines. Most of the reported cases have occurred within 30 minutes of vaccination. Individuals tend to recover quickly with appropriate treatment.

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

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

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

Guidance on reporting adverse events following immunization (AEFI)

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

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

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

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

Contraindications and precautions

Contraindications

In general, vaccines are contraindicated in individuals who are hypersensitive to the active ingredient or to any ingredient in the formulation, including any non-medicinal ingredient, or component of the container. For COVID-19 vaccines, in some cases, individuals with a known or suspected hypersensitivity may receive the vaccine under medical supervision. See Precautions for more details.

See Contraindications and precautions in Part 2 for more information on allergies.

Precautions

Hypersensitivity and allergies

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

In individuals with a history of a severe, immediate (4 hours or less following vaccination) allergic reaction after previous administration of an mRNA COVID-19 vaccine, re-vaccination may be offered with the same vaccine or the same platform if a risk assessment deems that the benefits outweigh the potential risks for the individual and if informed consent is provided. Consultation with an allergist or other appropriate physician should be sought prior to re-vaccination.

If re-vaccinated, vaccine administration should be done in a controlled setting with expertise and equipment to manage anaphylaxis. Individuals should be observed for at least 30 minutes after re-vaccination. A longer period of observation is warranted for individuals exhibiting any symptom suggestive of an evolving AEFI at the end of the 30-minute observation period.

Confirmed allergies to a component of a COVID-19 vaccine

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

All mRNA vaccines (Pfizer BioNTech, Moderna Spikevax and Moderna mNexspike) have polyethylene glycol (PEG) and tromethamine (trometamol or Tris) but no polysorbate 80.

Nuvaxovid has polysorbate 80 but no polyethylene glycol (PEG) or tromethamine (trometamol or Tris).

In individuals with a confirmed severe, immediate (≤4 hours following exposure) allergy (e.g., anaphylaxis) to a component of a specific COVID-19 vaccine (e.g., PEG), or its container, consultation with an allergist is recommended before receiving the specific COVID-19 vaccine. Individuals with a known or suspected serious allergy to a component of a COVID-19 vaccine for whom the vaccine is felt to be appropriate should be observed for at least 30 minutes after vaccination, if they receive a vaccine containing that component or have a proven serious allergic reaction to any injectable therapy (see Other allergy section below).

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

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

In individuals with mild to moderate immediate allergic reactions (defined as limited in the scope of symptoms and involvement of organ systems or even localized to the site of administration) to a previous dose of mRNA COVID-19 vaccine or any of its components, re-vaccination may be offered with the same vaccine or the same platform (i.e., mRNA). Assessment by a physician or nurse with expertise in immunization may be warranted prior to re-immunization. They should also be observed for an extended period of at least 30 minutes after re-vaccination.

Other allergies

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

30-minute post-vaccination observation period:

• Those with a proven severe allergic reaction (e.g., anaphylaxis) to injectable therapy not related to a component of the COVID-19 vaccines (e.g., other intramuscular, intravenous, or subcutaneous vaccines or therapies)
• Those with a suspected but unproven allergy to a vaccine component (e.g., PEG)

15-minute post-vaccination observation period:

• Those with a history of allergy not related to a component of the COVID-19 vaccines or other injectable therapy (e.g., those with allergies to foods, oral drugs, insect venom or environmental allergens)

Acute illness

Vaccination of individuals who may be currently infected with SARS-CoV-2 is not known to have a detrimental effect. However, vaccination should be deferred in individuals with confirmed or suspected SARS-CoV-2 infection, or those with respiratory symptoms, to minimize the risk of transmission of SARS-CoV-2 and other respiratory viruses at an immunization clinic/venue.

See the section Individuals previously infected with SARS-CoV-2 for additional information.

Bleeding disorders

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

Refer to Immunization of persons with chronic diseases in Part 3 for more information on the immunization of persons with bleeding disorders.

Myocarditis and/or pericarditis following vaccination

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

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

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

As with mRNA vaccines, Nuvaxovid has been associated with a rare risk of myocarditis/pericarditis. No guidance is currently available regarding re-vaccination for those who experienced myocarditis/pericarditis following the Nuvaxovid COVID-19 vaccine.

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

Guillain-Barré syndrome

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

Individuals with a history of GBS unrelated to COVID-19 vaccination should receive updated COVID-19 vaccines as recommended.

Bell's palsy

Individuals should seek medical attention if they develop symptoms compatible with Bell's palsy following receipt of mRNA COVID-19 vaccines. No guidance is currently available regarding re-vaccination for those who experienced Bell's palsy after an mRNA COVID-19 vaccine, however, as noted above, a causal association between mRNA COVID-19 vaccines and Bell's palsy has not been established. Based on the product monograph, Bell's palsy is not listed as an adverse reaction to Nuvaxovid.

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

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

Back to table of contents at top of page

Other considerations

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

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

Back to table of contents at top of page

Chapter revision process

This chapter was updated based on the Guidance on the use of COVID-19 vaccines starting fall 2026 (PDF) from the National Advisory Committee on Immunization (NACI). This chapter was also revised with information on updated COVID-19 vaccine products for use beginning fall 2026.

Back to table of contents at top of page

Acknowledgements

This chapter revision was prepared by C Jensen, R Krishnan, MI Salvadori, P Doyon-Plourde, B Warshawsky and N Forbes.

NACI gratefully acknowledges the contribution of: C Tremblay.

Back to table of contents at top of page

Selected references

• Abraham N, Spruin S, Rossi T, Fireman B, Zafack J, Blaser C, et al. Myocarditis and/or Pericarditis Risk After mRNA COVID-19 Vaccination: A Canadian Head to Head Comparison of BNT162b2 and mRNA-1273 Vaccines. JVAC-D-21-03106, Available at SSRN: https://ssrn.com/abstract=3988612
• Brighton Collaboration. Interim case definition of Thrombosis with Thrombocytopenia Syndrome (TTS) [Internet]. Decatur (GA): The Task Force for Global Health; 2021 Nov 11. Available from: https://brightoncollaboration.us/wp-content/uploads/2021/11/TTS-Updated-Brighton-Collaboration-Case-Defintion-Draft-Nov-11-2021.pdf
• Canadian Society of Allergy and Clinical Immunology. COVID-19 Vaccine Testing & Administration Guidance for Allergists/Immunologists from the CSACI. Accessed November 2021 at: https://www.csaci.ca/wp-content/uploads/2021/11/2021-11-15-UPDATE-COVID-19-Vaccine-Testing-Administration-Guidance.pdf
• Jennings, S., Corrin, T., and Waddell, L. (2023). A systematic review of the evidence on the associations and safety of COVID-19 vaccination and post COVID-19 condition. Epidemiology and Infection, 1-34. doi:10.1017/S0950268823001279
• McNeil, A. Updates to COVID-19 vaccine effectiveness [slides presented at the Advisory Committee on Immunization Practices meeting on June 25, 2025] [Internet]. Atlanta (GA): CDC; 2025 Jun 25 [cited 2025 Aug 22]. Available from: https://www.cdc.gov/acip/downloads/slides-2025-06-25-26/03-MacNeil-COVID-508.pdf
• Meyer, S. Update on CDC's COVID-19 vaccine safety monitoring [slides presented at the Advisory Committee on Immunization Practices meeting on June 25, 2025] [Internet]. Atlanta (GA): CDC; 2025 Jun 25 [cited 2025 Aug 22]. Available from: https://www.cdc.gov/acip/downloads/slides-2025-06-25-26/04-Meyer-COVID-508.pdf
• Moderna Biopharma Canada Corp. Product monograph - mNEXSPIKE™ July 6, 2026.
• Moderna Biopharma Canada Corp. Product monograph - SPIKEVAX^®June 19, 2026.
• National Advisory Committee on Immunization. COVID-19 vaccine statements. Accessed September 2025 from: https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci.html#covid-19
• Sanofi Vaccines Canada Ltd. Product monograph - NUVAXOVID^®June 19, 2026.
• Pfizer Canada ULC. Product monograph - COMIRNATY^®September 10, 2026.
• Public Health Ontario. Recommendations: Fourth COVID-19 vaccine dose for long-term care home residents and older adults in other congregate settings. December 29, 2021. Accessed February 2022 from: https://www.publichealthontario.ca/-/media/Documents/nCoV/Vaccines/2022/01/covid-19-oiac-4th-dose-recommendations-older-adults-ltc.pdf?sc_lang=en
• Therapeutic Goods Administration (Australia). COVID-19 vaccine safety report - 04-05-23. https://www.tga.gov.au/news/covid-19-vaccine-safety-reports/covid-19-vaccine-safety-report-04-05-23
• World Health Organization. Statement on the antigen composition of COVID-19 vaccines. 2025 May 15 [cited 2025 Aug 22]. Available from: https://www.who.int/news/item/15-05-2025-statement-on-the-antigen-composition-of-covid-19-vaccines

Back to table of contents at top of page