OTTAWA — Canada's Chief Medical Officers of Health say the benefits of vaccines authorized in Canada continue to outweigh the risks.
Friday's statement by the group said Infection with the virus that causes COVID-19 is linked to a wide variety of complications that can result in hospitalizations and/or death.
Myocarditis, touted often by anti-vaccine or vaccine-hesitant citizens as a dangerous side effect of the COVID-19 vaccines, is one of the known complications of COVID-19 infection, with much higher risks after infection than after vaccine.
The National Advisory Committee on Immunization has released updated guidance on the use of mRNA vaccine based on the most recent surveillance data from Canada, the Unted States and Europe, regarding rare cases of myocarditis and pericarditis following vaccination.
Cases of myocarditis and/or pericarditis after mRNA COVID-19 vaccination have been reported in approximately 1 in 50,000 or 0.002 per cent of doses administered.
The detection of rare events such as this is a demonstration that surveillance systems in Canada and globally are effective, said chief medical officers in their statement.
“Over 60 million doses of a COVID-19 vaccine have been administered to date in Canada, with serious effects remaining very rare (0.011 per cent of all doses administered).”
To mitigate the risk of myocarditis or pericarditis, which has been found to be somewhat higher for Moderna than Pfizer in adolescents and young adults, NACI recommends that the Pfizer-BioNTech 30 mcg product is preferred for the primary series in those 12 to 29 years of age. An 8-week interval between the first and second dose is recommended, as longer intervals such as this are likely to have less risk of myocarditis than shorter intervals and likely to result in improved protection. NACI has also indicated that the Pfizer-BioNTech 30 mcg product may be preferred for the booster dose in those 18 to 29 years of age. Adolescents and young adults 12 to 29 years of age who have already received one or two doses of the Moderna vaccine more than a few weeks ago do not need to be concerned, as the risk of myocarditis/pericarditis with this vaccine is rare and the adverse event usually occurs within a week following vaccination. Vaccination should not be deferred if the preferred product is not available at the time of vaccination.
The Council of Chief Medical Officers of Health includes the Chief Medical Officer of Health from each provincial and territorial jurisdiction, Canada's Chief Public Health Officer, the Chief Medical Advisor of Health Canada, the Chief Medical Officer of Public Health of Indigenous Services Canada, the Chief Medical Officer from the First Nations Health Authority, and ex-officio members from other federal government departments.
