Virulence of Omicron variant will shape Quebec's use of COVID-19 vaccine boosters

·4 min read

MONTREAL — The virulence of the Omicron variant of the novel coronavirus will be one of the factors that shapes whether Quebec makes third doses of COVID-19 vaccines more widely available, a member of Quebec's immunization committee said Wednesday.

On Wednesday, the province's Health Department said five cases of the variant have now been detected among travellers to the province and another seven cases remain under investigation. Authorities in the province had previously detected a single confirmed case of the Omicron variant.

The discovery of additional Omicron cases comes one day after the province announced it would expand access to third doses of COVID-19 vaccines to everyone 60 and over, pregnant women, health-care workers, people with certain chronic illnesses and those who live in remote communities.

Third doses had previously only been available to people 70 and over in the province, as well as those with compromised immune systems and people who received two doses of the Oxford-AstraZeneca vaccine.

Dr. Caroline Quach-Thanh of Quebec's immunization committee said it is possible the provincial government will decide people under 60 do not need a third dose, even though the National Advisory Committee on Immunization has recommended booster shots for those 50 and over.

If the Omicron variant causes mild infections "maybe what you should do is let people get it and, as long as it doesn't cause hospitalization and death, that boosts the immunity naturally and that will protect the population," she said in an interview Wednesday. If, however, the Omicron variant becomes more virulent, "then you want your population to be protected," she added.

While Quach-Thanh said the level of immunity provided by COVID-19 vaccines is declining over time across all age groups, "we haven't seen yet a change in the effectiveness of the vaccine against hospitalization and death, so that still seems to hold, which is great."

Quach-Thanh, who was the chair of the National Advisory Committee on Immunization until June, said she doesn't know why the Quebec committee and the federal committee have given different recommendations on the vaccination of people aged 50 to 59. The Quebec committee looked at the severity of the disease by age group, she said, adding that "those less than 60 are usually not at as high risk of complications."

Ontario is following NACI's advice and has said it will make third doses available to everyone 50 and over starting Dec. 13, while British Columbia has said it will gradually give everyone in the province a third dose by May 2022.

Dr. Donald Vinh, an infectious disease specialist and a medical microbiologist at the McGill University Health Centre, said he thinks Quebec has already hesitated too long before making third doses available to more people.

He said he now hopes Quebec doesn't wait to see proof that the vaccines are becoming less effective before expanding access to other age groups. Proof of loss of efficacy means people getting sick, some of whom may be hospitalized or die, he added.

"The whole purpose of immunization is to give the vaccines before people are sick, so they don't get sick, and waiting for people to get sick, which is what the current strategy seems to be, is a bit confusing," Vinh said in an interview Wednesday.

Alain Lamarre, a professor at Quebec's Institut national de la recherche scientifique who specializes in immunology and virology, said he thinks Quebec's approach is prudent and prioritizes the highest risk groups, adding that if vaccination were opened too quickly, lower risk people might take the place of those at higher risk.

Still, he expects Quebec will lower the minimum age for the third dose once it reaches the current target groups and that, eventually, it will be recommended for everyone. While the decline in immune response is smaller among younger people, he said in an interview Wednesday, even young and healthy people experience a decline.

New data on the Omicron variant suggests two doses of vaccine may offer less protection he said, meaning a third dose could help — especially if the variant is more contagious. "I think it's a good practice to continue with the third dose and expand it as much as possible to the whole population," he said.

Quebec reported 1,367 new cases of COVID-19 Wednesday and two additional deaths linked to the novel coronavirus.

The Health Department said the number of hospitalizations associated with COVID-19 rose by seven from the day before, to 242, and 59 people were in intensive care, an increase of one.

It said 87 per cent of Quebec residents aged five and over have received at least one dose of a COVID-19 vaccine, and 81 per cent are considered adequately vaccinated.

This report by The Canadian Press was first published Dec. 8, 2021.


This story was produced with the financial assistance of the Facebook and Canadian Press News Fellowship.

Jacob Serebrin, The Canadian Press

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