The following highlights key, current information for immunization providers on COVID-19 vaccines. The evidence on COVID-19 disease and vaccines is evolving. Evidence from clinical trial data is limited due to limitations in the size and duration of follow-up of trial populations; however, studies are ongoing. NACI will continue to monitor the data and update its recommendations as needed. Please refer to the remainder of the Statement for details.
Novel coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
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 work settings), and some populations are at increased risk of severe disease and death due to biological (e.g., advanced age, pre-existing medical conditions) and social (e.g., low socioeconomic status, belonging to a racialized population) factors that may intersect. Risk factors for exposure and severe disease may overlap, further increasing risk. Any combination of these factors, as well as varying access to health care services, has the potential for disproportionate consequences for specific populations.
Currently authorized vaccines
(Pfizer BioNTech COVID-19, Moderna COVID-19 vaccine)
These mRNA vaccines are authorized for use in Canada for individuals 16 years of age and older (Pfizer-BioNTech COVID-19 vaccine) or 18 years of age and older (Moderna COVID-19 vaccine).
In clinical trials, the vaccines are efficacious in the short-term against symptomatic, confirmed COVID-19 disease; trials are ongoing.
Protection offered by the first dose is lower than the efficacy achieved after the second dose and there are very limited data on duration of protection from one dose. Peak humoral and specific cellular immune responses occur after the second dose.
There is currently insufficient evidence on the duration of protection and on the efficacy of these vaccines in preventing death, hospitalization, asymptomatic infection and reducing transmission of SARS-CoV-2, although studies are ongoing.
No serious safety concerns related to the vaccines have been identified to date in clinical trials; however, studies are ongoing. For both vaccines, some solicited adverse events are reported to be very common (defined as 10% or more) among vaccinees. However, they are mild or moderate and transient, resolving within a few days. These include: pain at the injection site, fatigue, headache, muscle pain, chills, joint pain, and fever. Some adverse events, including fever, are more frequent after the second dose.
There is currently minimal evidence to inform on differences in vaccine efficacy or safety between those with and those without prior evidence of SARS-CoV-2 infection at the time of vaccination.
A complete vaccine series with a currently authorized COVID-19 vaccine should be offered to:
Individuals in the authorized age group without contraindications to the vaccine. In the context of limited vaccine supply, initial doses of COVID-19 vaccine(s) should be prioritized for the key populations outlined in NACI’s Guidance on the Prioritization of Initial Doses of COVID-19 Vaccine(s).
A complete vaccine series with a currently authorized COVID-19 vaccine may be offered to:
Individuals in the authorized age group without contraindications to the vaccine who have had previously polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection. In the context of limited vaccine supply, initial doses may be prioritized for those who have not had previously PCR-confirmed SARS-CoV-2 infection. Testing for previous SARS-CoV-2 infection is not needed prior to COVID-19 vaccination.
For some specific populations who were either excluded from, or were represented by small numbers of participants in clinical trials, NACI recommends that a complete vaccine series with a currently authorized COVID-19 vaccine may be offered, if a risk assessment deems that the benefits of vaccination outweigh the potential risks for the individual (e.g., where the risk of severe outcomes of COVID-19 and/or risk of exposure to SARS-CoV-2 is high) or for the fetus/infant (in the case of pregnancy/breastfeeding) and if informed consent includes discussion about the insufficient evidence in these populations:
Immunosuppressed due to disease or treatment
Individuals with an autoimmune condition
Pregnant or breastfeeding
Adolescents 12 to 15 years of age (Only Pfizer-BioNTech COVID-19 vaccine may be offered)
These recommendations may change as more evidence on safety and/or effectiveness in these populations becomes available.
Currently authorized COVID-19 vaccines are administered intramuscularly in a two-dose schedule.
Attempts should be made to complete the vaccine series with the same vaccine product.
Serologic testing is not needed before or after receipt of a COVID-19 vaccine to assess susceptibility to SARS-CoV-2 or immune response to the vaccine.
COVID-19 vaccines should not be given simultaneously with other live or inactivated vaccines at this time, unless other vaccines are required for post-exposure prophylaxis.
COVID-19 vaccines should not be given simultaneously with monoclonal antibodies or convalescent plasma.
The COVID-19 pandemic has caused significant morbidity and mortality, as well as social and economic disruption in Canada and worldwide.
The authorized COVID-19 vaccines that are recommended for use by NACI in this Statement have been shown to be safe, as well as efficacious against symptomatic laboratory-confirmed COVID-19 disease.