Flu shot this winter only up to 10% effective, Quebec Public Health says

The flu vaccine that Quebecers received this winter has not been as effective as hoped — attaining a success rate between zero and 10 per cent, according to the Quebec Public Health Agency.

“It’s always surprising to get data like this but we know it’s a possibility and, in transparency, we want to share this information with people,” said Dr. Horacio Arruda, director of Quebec Public Health.

That’s the first time we see no protection given by the vaccine.- Dr. Gaston De Serres, epidemiologist at National Institute of Public Health of Quebec

The data was recently revealed in a report published in the Eurosurveillance medical journal.

“We were surprised. We’ve been monitoring the effectiveness of the vaccine for a number of years, and that’s the first time we see no protection given by the vaccine. So it’s really an anomaly, and it’s not the rule,” said Dr. Gaston De Serres, an epidemiologist at the National Institute of Public Health of Quebec who participated in the study.

The typical success rate for a flu vaccine is between 50 and 70 per cent.

Prediction challenges

De Serres said the low success rate of this year’s flu vaccine is tied to the challenge in predicting what strains will hit the hardest.

​“The way that strains are selected to include in the vaccine is not a lottery, but it’s really difficult,” said De Serres.

This year’s vaccine, which was prepared by World Health Organization virologists in February 2014, included Influenza A, Influenza B, and H1N1. By the time the vaccine was administered to the public nine months later, Influenza A had evolved to hit much harder than the other two strains.

Better flu vaccine needed, experts say

De Serres said this year’s low success rate shows the need for a more reliable flu vaccine.

“We need to develop a better vaccine, and research efforts need to be allocated for the development of a better vaccine that would not be as erratic as the current vaccine,” said De Serres.

Dr. Karl Weiss, an infectious disease specialist at the Maisonneuve-Rosemont Hospital, says that this year’s flu vaccine was not strong enough.

“This is definitely not a good vaccine — it’s a complete mismatch. It raises overall issues on the strength of this flu vaccine. We are at a stage where we have to think about ... re-inventing this flu vaccine.”

Weiss says he’d like to see a vaccine that lasts longer than one flu season, adding that it would also cut down on costs.

Arruda agrees that more research on flu vaccines needs to be done. He says he hopes the public will continue to get a flu shot every year because it is usually effective.

This year the Quebec Health Ministry spent more than $13 million on the flu vaccine.