Calgary

This year's vaccine 72% effective at preventing flu, scientists say

This year’s flu shot has been 72 per cent effective at preventing infections in Canada, researchers say.

Calgary doctor who runs surveillance network in Alberta says to expect a further late-season epidemic

Dr. James Dickinson says part of the reason that this year's vaccine has been so effective is that H1N1 has mutated less quickly than H3N2, which was the dominant strain in last year's flu epidemic. (Robert Short/CBC)

This year's flu shot has been 72 per cent effective at preventing infections in Canada, according to a scientific study.

The interim estimate was published by Canadian researchers in Eurosurveillance, a European journal on infectious diseases and epidemiology.

The data came from the Canadian Sentinel Practitioner Surveillance Network, which provides samples that are used to determine the effectiveness of the flu vaccine. Results are shared with the World Health Organization (WHO) to help determine how to formulate the flu vaccine for the following season.

Alberta has about 70 doctors in the network who swab patients suspected of having the flu.

University of Calgary Dr. James Dickinson, a professor with the Cumming School of Medicine who leads the surveillance network in Alberta, says doctors who participate in the program are providing an important service.

"We've got about 80 doing this on a fairly regular basis. We'd like to have another 20 or 30 more if we could, particularly we need more representation in the north of the province," he said.

"The more that we have, the better estimates that we are able to get, and the earlier we're able to get — particularly our mid-season estimates like this one, which are very important to understand and to help people decide on policy for the rest of the season."

The mid-season vaccine efficacy estimate was only 20 per cent last year during the H3N2-dominant flu epidemic, the study said.

So far this flu season, H1N1 has been the dominant strain, with over 1,100 people having been admitted to hospital in Alberta.

The flu-related death toll in Alberta has reached 25.

Dickinson says part of the reason that this year's vaccine has been so effective is that H1N1 has mutated less quickly than H3N2.

"So the prediction that was made by the World Health Organization experts in February or March last year turned out to be pretty correct," he said.

Dickinson says the number of cases has begun to drop, but he says from past experience, we can expect a further late-season epidemic.

He says it is still worthwhile to get a flu shot.