OTTAWA — The National Advisory Committee on Immunization (NACI) has expanded eligibility guidelines for booster shots of COVID-19 vaccines.
NACI's latest guidelines suggest provinces could offer boosters to Canadians who received two doses of the Oxford-AstraZeneca vaccine or one dose of the Janssen vaccine.
The evidence suggests those vaccines may offer waning immunity over time.
The committee also suggests a third shot is an option for people over 70 who could become severely ill from the disease, as well as people from First Nations, Inuit and Métis communities.
Finally, NACI said front-line health-care workers with a short interval between their first two doses may also be offered another vaccine.
"Emerging evidence suggests vaccine effectiveness against asymptomatic infection and mild COVID-19 disease may decrease over time," NACI wrote in its new guidance Friday.
"A booster dose could help restore and maintain protection against infection in certain populations."
NACI more strongly recommends boosters for adults living in long-term care homes and other congregate living situations and adults over the age of 80.
The committee continues to recommend boosters be given six months after the first two doses are received.
NACI found no evidence of widespread waning immunity against severe disease in the general population.
"We are seeing that two doses of mRNA COVID-19 vaccines continue to perform very well for the majority of people," said NACI chair Dr. Shelley Deeks in a statement Friday.
That means the general population isn't likely to need a booster any time soon, said Canada's chief public health officer Dr. Theresa Tam.
While NACI has recommended boosters for some groups, Tam said she doesn't expect Canada to change its definition of full vaccination to include a third dose.
"We have to consider the fact that many countries don't even have enough vaccine to complete the primary series," Tam said at a briefing Friday.
"We have to balance both the scientific facts, the recommendations … but also the reality of the vaccine supply and equity from a global perspective as well."
Prime Minister Justin Trudeau was asked about Canada's move toward booster shots when many countries are still struggling to vaccinate its citizens during his official visit to the Netherlands Friday.
There are enough vaccines in the country to ensure every Canadian can get a full slate of vaccines, and the government will continue to work on ensuring vaccine access around the globe as well, Trudeau said.
Some provinces are already moving ahead with plans to offer boosters to the general population.
British Columbia has promised anyone in the province wanting a booster shot of a mRNA COVID-19 vaccine will have access to one by May 2022.
This report by The Canadian Press was first published Oct. 29, 2021.
Laura Osman, The Canadian Press