All Canadians over 50 should get a COVID-19 booster shot, immunization committee says in new guidance

In a new report issued today, the National Advisory Committee on Immunization (NACI) is now strongly recommending all Canadians over the age of 50 and other vulnerable groups like health-care workers, Indigenous peoples and those living in congregate care settings get a third dose of an mRNA COVID-19 vaccine.

The committee, an independent body composed of volunteer vaccine experts, is also now recommending the younger cohort — Canadians aged 18 to 49 — get a third mRNA shot at least six months after they got their second.

Advisory panels in other countries, like the one that works with the U.S. Centers for Disease Control (CDC), have for weeks recommended an expansion to the booster shot campaign to cover more people with the virus still circulating widely.

NACI is making these recommendations now because it said there is emerging data that suggest protection against infection is decreasing over time for those who completed a two-dose regimen.

"Decreasing protection against infection could contribute to increased transmission, since infected individuals may be a source of infection for others. Therefore, a booster dose may provide more durable protection to reduce infection, transmission, and in some populations, severe disease," the committee said in its report.