Boosting boosters: Experts say fourth doses not yet needed for general population

Many jurisdictions have extended fourth-dose boosters to their most vulnerable populations as Canada's third-dose COVID-19 vaccine rollout ramps up, leading some to wonder whether we'll all need another shot to protect against the virus in the near future.

Prime Minister Justin Trudeau said Monday that the country will have enough third and fourth doses for all eligible Canadians -- if or when they're needed -- with contracts signed through 2024 with Pfizer-BioNTech and Moderna.

Dr. Allison McGeer, a microbiologist and infectious disease consultant in Toronto, said Canada isn't at the point where fourth doses are necessary for the general population.

But will we get there somewhere down the road? Perhaps.

"I'm not sure where that point is," she said. "We know with other vaccines that sometimes you need three doses or four doses to get a prolonged, stable effect.