A few countries have started administering a third dose of COVID-19 vaccine to their populations. Quebec is preparing to offer it to its elders living in closed environments. What do scientists think of this third dose?
Member of the Quebec Immunization Committee, Dr Gaston De Serres explains that one of the reasons that motivated such a recommendation to the Quebec government is the drop in immunity against COVID-19 six months after the second dose of the vaccine, a drop that has been observed in some studies conducted in other countries, like israel, the United Kingdom and the United States. “Even if we do not have data here in Quebec on maintaining the efficacy of the vaccine in people in CHSLDs and RPAs, the data published elsewhere as well as the rise in outbreaks in CHSLDs and RPAs over the past few weeks encouraged us to recommend this third dose for prevention, ”he explains.
Another reason given: the great age and the great fragility of people living in CHSLDs and RPAs. “In these fragile people, the infection [la COVID-19] can be more serious than in younger, healthy people, he notes. It should also be remembered that the effectiveness of the vaccine is not 100%. If someone brings the virus into one of these closed settings, there will be vaccinated people who will develop the infection and some of them may have a serious infection and die from it because they are such frail people that they are so frail. ‘one infection may be enough to kill them. “
For his part, the Dr Don Vinh reminds that a third dose is absolutely necessary for people who are immunocompromised, transplanted, on dialysis or suffering from cancer first who develop weaker immune protection following the double vaccination than the general population.
The decision to offer a third booster dose also to seniors is “prudent”, he believes, given “community transmission. [du virus] which remains high ”,“ outbreaks in CHSLDs and RPAs ”and“ data from other countries which indicate a decrease in antibody levels over time ”.
The efficacy of the vaccine is not 100%. If someone introduces the virus into one of these closed settings, there will be vaccinated people who will develop the infection and some of them may have a serious infection and die from it.
The Dr Vinh also notes that “the administration of a third dose to people who have been adequately vaccinated will not however change anything for those who are not vaccinated”. “Among people aged 60 and over who are hospitalized due to COVID-19 in our hospital [le CUSM], almost 95% are not vaccinated, ”he emphasizes.
Experts agree, however, that this third booster dose is not justified for the entire population, because the double vaccination remains very effective against severe forms.