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COVID-19 booster doses: Dr. Jerome Leis answers some common questions

Written by Alexis Dobranowski

With Omicron widely circulating in Ontario, Sunnybrook Medical Director of Infection Prevention and Control, Dr. Jerome Leis, answered some common questions about COVID-19 vaccine booster shots.

Should I get a booster and when?

Yes. If you have not already done so, get your booster dose. Being fully vaccinated should now mean getting your booster as well, and that’s the best way to be well protected against any serious complications from COVID-19. In Ontario, you are eligible for a booster if you are 18 or older and your second dose was at least 84 days ago.

Why do we need boosters?

Two doses of mRNA vaccines did a good job of protecting us against SARS-CoV-2, the virus that causes COVID-19. Over time, though, immune systems’ response to vaccination can begin to fade. That’s why a booster dose is needed. After the Omicron wave passes, the strategy for long-term vaccination against COVID-19 will be revisited but for now getting your booster is the best protection we have.

I see there’s still people with boosters testing positive, so what’s the point?

Yes, people with two vaccine doses and even three vaccine doses can test positive for COVID-19. With other variants of COVID-19, the vaccines did a good job of both stopping transmission of the virus to vaccinated people and preventing serious illness in vaccinated people. With the Omicron variant, the vaccine doesn’t stop all transmission. But, vaccination is still extremely effective at preventing serious illness and hospitalization caused by Omicron which is the most important goal of vaccination and reducing the impact of the pandemic on our daily lives. By reducing disease severity, we preserve our healthcare system capacity, which means that fewer public health restrictions will be necessary over time and the overall impact of the pandemic on our daily lives will lessen.

I heard some people are getting a fourth dose? Who?

People with certain immunocompromising conditions like recent stem cell transplants or organ transplants were given a “three-dose primary series.” This means to be fully vaccinated, folks with these specific illnesses were given three doses whereas the general population had two. Some of these people are now eligible for a fourth dose — their booster. You can find more info here. If you had an organ transplant or stem cell transplants or are in active treatment for cancer, please speak to your healthcare provider or learn how to book at this provincial booking link. In addition, residents of long-term care homes are being offered a fourth dose of a COVID-19 vaccine. This is to offer additional ongoing protecting to this vulnerable population.

I had COVID recently – when should I get a booster?

Update February 7, 2022: Canada’s National Advisory Committee on Immunization (NACI) now recommends that any vaccinated Canadian who gets infected with SARS-CoV-2 should wait three months before getting a COVID-19 booster shot. Read more about these new recommendations.

If you had COVID-19 after December 15 in Ontario, you’ve likely had Omicron already. If this is the case, there is no rush in getting a COVID-19 booster. We do know that natural immunity can begin to wane within a few months and for this reason vaccination has still been recommended among those who have recovered from COVID-19 once they have fully recovered. The optimal timing for that booster is not yet known but usually it is recommended you get it by three months from the infection.

My kid is 15 and was vaccinated as soon as they were able. Now that was a long time ago! When can they get a booster?

In Ontario, the booster shot has not yet been approved for those 12-17. The CDC in the United States recently announced approval for this population and it’s likely Canada and Ontario will follow suit too. We will update this page once we have more information.

I heard it’s only Moderna right now in Ontario for adult boosters, and I want Pfizer. What should I do?

In Ontario there is currently a Moderna-first approach. Adults age 30+ receive Moderna for their third dose and those under 30 may receive Pfizer based on availability. With Omicron widely circulating and the strong evidence that vaccination greatly reduces the risk of hospitalization and poor outcomes irrespective of the vaccine brand received, please take the booster shot that is available to you right now.

Sunnybrook’s Vaccine Clinic is closed to the public as Sunnybrook is currently focused on vaccinating staff and their households. To find a vaccine clinic near you, visit Ministry of Health’s website or the City of Toronto’s website.

About the author

Alexis Dobranowski

Alexis Dobranowski is a Communications Advisor at Sunnybrook.