(Montreal) The flu vaccine currently has an overall effectiveness rate of 58% this year, which is a good performance, according to a Quebec expert who participated in the interim report on this vaccine.
Posted on February 21, 2020, 5:26 p.m.
The vaccine had not been as effective since the 2013-2014 season, when it had had a rate of 68%.
Last year, for comparison, the overall effectiveness of the flu vaccine was 56%.
The current flu season is characterized by a co-circulation of influenza A and B viruses.
More specifically, it is a strong circulation of influenza B, and, for influenza A, the majority is H1N1 (80%), and in a smaller proportion, H3N2 ( 20%).
“The three big players circulate at the same time in Canada,” commented Dr. Gaston De Serres, doctor-epidemiologist and researcher, notably at the National Institute of Public Health of Quebec (INSPQ).
He is part of the Canadian Sentinel Practitioner Surveillance Network, a network dedicated to measuring the effectiveness of the flu vaccine every year, the results of which are published in the journal “Eurosurveillance”.
In short, “overall, we have a protection of 58%”, noted the Dr From Serres.
He points out that it is higher against type B influenza: its effectiveness has been measured at 69%. Which is good news, he says, because influenza B is the most circulating during the current flu season.
As for the effectiveness of the influenza A (H1N1) vaccine, it is 44% and 62% against A (H3N2).
For H3N2, this is a “surprising performance”, underlines the expert, who recalls that in past years, the protection offered by the vaccine has hovered around 30% or 40%.
On the other hand, for H1N1, the protection is weaker this year.
These results may still fluctuate because the flu season is not over. The review “Eurosurveillance” will also update its results.