Saturday, December 4

A third dose to face the holidays?

France and the United Kingdom go into fourth gear and offer a third dose to their adult population to check the virus before Christmas. Should Quebec follow suit? Experts believe that it is “one to midnight” for hundreds of thousands of Quebecers who have been vaccinated for more than six months.

The fifth wave sweeping over Europe took a new turn on Thursday with the urgent call for France to generalize the granting of a booster dose to the entire adult population from next Saturday. The French High Authority of Health has even reduced from six to five months the minimum time between the second dose and the booster dose, now essential for people 65 and over to keep a valid health passport.

The United Kingdom is also taking great steps to give a third dose to those over 40 before December 11, in a race to avoid high transmission during the Christmas and New Year festivities.

Struggling with outbreaks of infections since the fall, Europe is struggling with a fifth wave that could kill up to 700,000 by spring, according to the World Health Organization.

In Quebec, as the number of cases increases, the voices are multiplying to request the administration of a booster dose to the entire population. And this, in order to avoid a backlash of infections among doubly vaccinated, such as those observed in Europe, especially in the United Kingdom.

“It is the train of science that must be followed, not that of the politicians. And science tells us that the immunity provided by the vaccine wanes after six months. You have to be agile, fast. Do not wait for the disaster, ”says Roxane Borgès Da Silva, professor at the School of Public Health at the University of Montreal.

As the holidays approach, we must offer greater protection to Quebecers. “It would be doable to do this quickly, at the same time as the campaign for children,” she believes.

Suspended immunity

According to figures compiled by The duty Based on public data from the National Institute of Public Health of Quebec (INSPQ), just over 2.3 million Quebecers will have received their second dose for more than six months during the month of December. By the end of January, that number will reach 4.8 million.

Professor André Veillette, researcher in immunology at the Montreal Clinical Research Institute and member of the federal working group on COVID-19 vaccines, reports that several studies have identified a decline in immunity well before six months.

“For health care workers who received their second dose in March or April, it is more than one to midnight before outbreaks resurface in hospitals treating vulnerable patients,” he urges.

A study conducted in Israel among 80,000 patients doubly vaccinated with the vaccine from Pfizer-BioNtech, published Thursday in the British Medical Journal, reveals that the protection against infection in these people had halved after four months, and was 10 times less after six months. However, the vaccine remained effective in preventing hospitalizations for six months.

“We are not genetically different from Europeans or even from people of British Columbia, where we have seen that the immunity of vaccinated people has already started to decline. The vaccine is available, it costs $ 20, it boosts protection by 60-90%, so why wait for cases to increase? »Emphasizes André Veillette. British Columbia has extended access to the third dose to everyone, a measure that will take effect in January 2022. This is also the case in Manitoba.

According to this expert in immunology, the high vaccination rate achieved in Quebec does not protect the population from the decline in immunity inherent in current vaccines. It is the maintenance of health measures, combined with the high vaccination coverage, which explains the enviable situation of Quebec compared to certain European countries which have also achieved good vaccination rates. France, the Netherlands, the United Kingdom, Germany and several Scandinavian countries in particular relaxed health restrictions too quickly and are now paying the price, he said. Iceland, Denmark and Germany have just extended the booster dose to all their residents.

Different data

But according to the INSPQ, for the moment, nothing justifies granting Quebec a booster dose to all. “Europe stands out from us on several criteria. A 10% difference in vaccination coverage is huge, and there, we acted this fall as if COVID no longer existed by lifting several health measures, ”says Dr.r Gaston De Serres, medical consultant at the INSPQ.

For now, close monitoring of people vaccinated in Quebec shows that the efficacy of the vaccine is maintained, even beyond seven months. The INSPQ maintains that the spacing of the two offered doses has been found to be more effective in prolonging immunity against the virus. “We are monitoring this closely with our local data to see if there is a decrease in efficiency. Should we do like other countries just as a precaution? In the United States, they introduced the third dose for the entire population even before there was any scientific evidence that it was useful, ”he says. The Quebec Immunization Committee will soon provide an update on the surveillance of immunity conferred by vaccines.

The virologist and immunologist André Lamarre, professor and researcher at the National Institute of Scientific Research, for his part, argues that a “third dose is inevitable sooner rather than later”. “We won’t have a choice. I believe we have reached the fateful six months for those 50 and over. It is already outdated for many health care workers. It starts to press. We must prevent rather than react. “

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