From Monday, a 4and dose of vaccine against COVID-19 will be accessible to people aged 60 and over who wish to obtain it, but this booster dose is not officially recommended by the Comité sur l’immunization du Québec. However, this “lukewarm” position is not unanimous among the experts, while some are worried about the confusion it could cause. The newspaper make the point.
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What does Public Health say about the 4and dose for 60 and over?
Gaston De Serres
“What the ministry has announced is not that we recommend vaccination for people aged 60 and over, but those who want the 2and booster dose can have access to it”, specifies from the outset Gaston De Serres, epidemiologist at the National Institute of Public Health of Quebec and member of the Committee on Immunization of Quebec (CIQ).
“The benefits seem much less obvious to us” than for other groups, such as people aged 80 and over for whom the 4and dose is recommended, he adds.
The majority of studies have shown, after a certain time, a decline in the effectiveness of vaccines against infection, but the reduction in protection against hospitalizations linked to severe forms of the disease “is much less marked”, explains the epidemiologist.
Should healthy people over 60 get vaccinated?
Photo archives, Martin Alarie
Opinions are divided. “There will be a gain, but it probably won’t be very big,” says the Dr De Serres, since the sixth wave is already well underway. “A vaccine is good when you receive it before the epidemiological wave”, he specifies.
Alain Lamarre, specialist in immunology and virology at INRS, affirms on the contrary that the gain is very real.
According to a study published earlier this week in the New England Journal of Medicinethe 4and dose in people aged 60 and over would quadruple the level of protection against severe forms of the disease up to six weeks after injection.
“There is a significant benefit” to receiving this booster dose since the immunity conferred by the third dose decreases over time, he says.
Could access to the drug Paxlovid avoid the need for booster doses?
No, according to the two experts consulted.
Paxlovid remains effective in preventing severe forms of the disease, but only if given quickly.
However, rapid tests have more difficulty in rapidly detecting the BA.2 sub-variant, so that several days may pass before obtaining a positive result.
Access to this drug, on sale in pharmacies since April 1, is also reserved for people at risk of complications.
Should we be afraid of repeated vaccines?
Apart from the side effects already known, there is no indication for the moment that the injection of a fourth dose of vaccine in a short period could alter the immune response against COVID-19, says Gaston De Serres .
For his part, Alain Lamarre believes that these repeated vaccines could lead to “less effectiveness over time”, a risk which is however far from having been demonstrated.
Since the benefits are greater than the apprehended risks, he considers that a person aged 60 and over “has not much to lose” by going to get his 4and dose.
An interval of at least three months between doses is necessary.