Here's Why Some Canadians Might Need A Third COVID-19 Vaccine Dose According To An Expert

Narcity spoke to Dr. Joanne Langley, a vaccine researcher and infectious disease physician at Dalhousie University. Dr. Langley is currently part of the MOSAIC Study, which is working to collect data on mixing and matching COVID-19 vaccines among other things.

We asked Langley about COVID-19 booster shots and whether or not she believed that they will be necessary down the road to provide ongoing protection against COVID-19. "We don't know yet whether we'll need those boosters or which sub populations might need boosters. So we'll know once we know how long the immune protection from the vaccines that we're using lasts," she told us.

In order to determine if boosters are needed, researchers will need to find out how long immune responses will last after the first two doses.

A third COVID-19 vaccine dose

While Langley says that we don't know much about the necessity for booster shots at the moment, "we do know that there are some people who don't respond to two doses of authorized vaccine."

"Older people and immunocompromised people are the ones who 'fail' vaccination. So even after [two doses], some of those people will still get COVID. And so there are clinical trials going on now using a third. There's one in Toronto and there's [one] in Israel, they're routinely giving a third dose now to people."

When asked if third doses could potentially be required in Canada for those who aren't responding to second doses, Langley said "That may be the case, we will see. [...] With other vaccines, non-COVID vaccines, there are times when we use more vaccine doses than we would in someone who has a normal immune system."

So, according to Dr. Langley, what we know about COVID-19 booster vaccines is twofold. First, we need to wait and see what the length of vaccination coverage is to determine if we need boosters in the future. And second, some people may need third doses if they haven't responded to the second.

Though, in Canada, most COVID-19 cases are being detected in unvaccinated people.

Regardless if we will require boosters or not, the federal government has secured additional doses to be used in the event that boosters become necessary.

Health Canada has a robust website with all the latest information on COVID-19 vaccines and can answer any questions you may have.