Canada should have abandoned seasonal flu shot to focus on H1N1: critics

With H1N1 now accounting for virtually all the flu being diagnosed in Canada, critics say Canada was wrong not to have halted production of the regular seasonal flu shots and switched production to H1N1 vaccine sooner.

"I believe that if they had made the bold and courageous decision to follow the evidence, and abandon the seasonal flu vaccine, that we could have had our H1N1 vaccine about six weeks earlier," says Dr. Richard Schabas, Ontario’s former chief medical officer of health.

"The consequence of that is that we’ve got lots of seasonal flu vaccine, but no seasonal flu, and not enough H1N1 vaccine, and lots of H1N1," Schabas said. "It’s backwards."

For the week ending Oct. 31, a total of 7,970 specimens tested positive for influenza. Overall, 99.7 per cent were pandemic H1N1. Infections and hospitalizations have been increasing, and most provinces and territories have delayed all or parts of their regular seasonal influenza programs until after the H1N1 vaccination campaign is complete.

Schabas said there were early signals H1N1 would be the dominant strain this flu season. A phenomenon known as "strain replacement," where the new virus replaces old ones that had been circulating, is a classic characteristic of a pandemic virus.

"That’s what happened in 1918, it’s what happened in 1957 and it’s what happened in 1968," says Schabas, now medical officer of health for Ontario’s Hastings and Prince Edward Counties Health Unit.

In the Southern Hemisphere, where the flu season runs from April to September, H1N1 began to be prevalent in May, and then increasingly became the predominant strain.

"There was strong reason to believe that there would be strain replacement, that we would not see significant levels of seasonal flu activity this year," Schabas said. He said enough seasonal flu vaccine could have been produced to offer immunization to people over 65, and those with chronic diseases who are at high risk of flu complications, before shifting production to targeting H1N1.

"The best time to immunize is before the outbreak starts. We’re not going to actually be able to even offer the vaccine to healthy people until the outbreaks are largely over, at least in many parts of the country," Schabas said.

"That, to my mind, makes it inappropriate to be immunizing healthy people, at least in those parts of Canada where the outbreaks are already past the peaks," he said.

"By the time we’re able to offer it in Ontario, this outbreak will be past its peak in Ontario."

Canada’s top doctor said that when the decision was made in July to keep producing seasonal flu shots, some countries in the Southern Hemisphere were seeing as much seasonal influenza as H1N1.

"Once you stop the seasonal flu production, it is done," Dr. David Butler-Jones said at a recent media briefing.

"It meant . . . a short delay, in the H1N1 production, but it also means that we have, and will have seasonal flu vaccine for all those who need and want it as well.

"You would not want to be in a situation where, if we’d stopped it, we’d run out so we can’t actually immunize against seasonal flu, and we have people seriously ill and dying from seasonal flu."

Earl Brown, a University of Ottawa virologist, said it was not clear in the summer whether H1N1 would come back hard. As well, there were early problems with the seed strains used to grow the virus to produce the H1N1 vaccine.

"The first ones were bad and the next ones weren’t much better, and they had to work at it to get something that was even acceptable," said Brown, executive director of the Emerging Pathogens Research Centre at the University of Ottawa.

"Even if they said, ‘Let’s stop now and go,’ they weren’t ready to go. If they had stopped annual flu production, they would have been sitting there on their hands, with idle factories without any seasonal flu (vaccine)."

Seasonal flu epidemics typically last six to eight weeks, starting in December or January. The second wave of H1N1 appears to have begun about two weeks ago. But experts caution there isn’t a pattern that is strong enough to predict where we are with H1N1.

The World Health Organization reported Friday that "intense and persistent" flu spread continues to be reported in North America, without evidence of a peak in activity. According to WHO, the proportion of doctors visits due to flu-like illness has exceeded levels seen over the past six flu seasons.

Typically flu infects about 10 per cent of the population each year. In the 1918 influenza pandemic, half the North American population was infected.

"We don’t know how many people have been infected, or how this thing is going to go," Brown says.

But Brown cautions hysteria can drive people to the doctor when they don’t need to go. "You have to be careful in reading the things you normally use as signifiers, because sometimes they’re skewed because of behaviour changes.

"The things you can’t fake are the hospitalizations and the ICU (admissions). You can’t fake an ICU. You’re either on death’s door or not. Looking at those numbers; they’re not at the summer levels yet."

HangZhou Night Net

Comments are closed.

Post Navigation