Quebecers with compromised immune systems can now get a third dose of a COVID-19 vaccine

Montreal -

Quebecers with compromised immune systems and those undergoing dialysis can now get a third dose of a COVID-19 vaccine.

The announcement came just hours after the province’s Public Health Institute (INSPQ) recommended measures be taken to better protect immunocompromised people. 

“This additional dose should be considered as a reinforcement of the basic vaccination and not as a booster dose,” read a statement published by the INSPQ. 

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Immunocompromised people often “do not respond to the first two doses due to a medical condition that affects their immune system,” according to Committee on Immunization of Quebec President Dr. Nicholas Brousseau.

He says those needing a third shot should get it at least four weeks after their second.

The updated measures only affect about one to two per cent of the population, according to the Institute.

While the Institute says there is limited data surrounding the safety of administering more than two shots, it says “no serious adverse reactions” have been reported among immunosuppressed people during trials.

On the contrary, the Institute wrote that “people with an immune deficiency resulting in a poorer response to vaccines” experience fewer and less-intense reactions after getting their shot than people with normal immune systems.

While it remains unknown exactly how much a third shot would benefit them, the INSPQ says that it’s “highly likely” that immunocompromised people will be better protected with an additional shot.

As for what kind of shot should be used, the INSPQ says mRNA vaccines (such as Pfizer and Moderna) are preferred over viral-vector shots, such as AstraZeneca or Johnson & Johnson.

An mRNA shot should be used even if the patient has already received two viral-vector doses. 

This is a developing story.