Alberta health officials question effectiveness of this year’s flu shot

It is not quite influenza season yet and already Alberta health officials are troubled by what they're hearing: that the new vaccine is showing little effectiveness against this year's flu virus.

A year ago, Alberta was ravaged by a flu virus that put 1,874 people in hospital and left 103 others dead. It was caused by an A-type strain (H3N2) that mutated to the point where the vaccine was of no help. There have been three outbreaks of flu reported in British Columbia already – more than expected for this time of year, and before most people get vaccinated.

The hope for this autumn was to get the right ingredients together to work their magic before the start of winter. Instead, there is a growing concern that the mix is off and, once again, people are at risk, especially the elderly and the very young.

"There have been some changes made to the vaccine based on last year's very poor performance," said Glen Armstrong, a University of Calgary professor in the department of microbiology, immunology and infectious diseases.

"The problem with all the vaccines is the H3N2 component," Prof. Armstrong said. "If that turns out to be dominant – and there have been a couple of cases in B.C. that suggest this is the strain that hit first – then the vaccine has never been that good."

Adding or subtracting strains to best combat a virus is in many ways a roll of the dice. Doctors and Alberta Health Service workers pass their flu data on to the province's Ministry of Health, which passes it along to Public Health Agency of Canada. All that is available to the World Health Organization (WHO), which surveys its member countries before deciding what should be done to flush the flu.

The WHO examines trends and what kinds of viruses are coming out of southern hemisphere countries in time to infect northern hemisphere countries preparing for winter. There is also a timing matter. The vaccines take six to nine months to be manufactured. Provinces have to look at yearly trends, then decide how many vaccines are needed.

"The thing we have to remember is that in the course of a flu season there is usually more than one strain," said Gerry Predy, Alberta Health Services senior medical officer. "Last year's vaccine was protective against two strains but not against one. That's the thing we try to emphasize, that the vaccine is trying to protect against three different strains, and it's not unusual during the course of a season to see at least two circulate."

For this coming flu season, the AHS has what it calls multiple vaccine products. There are five products available through the province's flu program – two of the five products are quadrivalent, meaning they can safeguard against four strains – and three are trivalent. All products protect against the strains expected to circulate this season. Albertans will be immunized with the available product most appropriate for them, based on age, health history and health status.

Asked if the province has ordered and stored away enough vaccine to handle a wave of outbreaks, Dr. Predy answered: "It's [the ministry's] decision. It isn't an easy decision to make, but they make it based on the info that they have. We certainly believe we have enough vaccine this year."

For its 2015-16 needs, Alberta Health has enough vaccine to cover 40 per cent of the population. More than a million people were vaccinated last year. That meant 29 per cent of Albertans were immunized.