Though the long-discussed second wave of H1N1 likely crested weeks ago, that doesn't mean the virus is gone, warns Dr. David Butler-Jones.
Canada's chief public health officer told Canada AM that flu viruses are notoriously unpredictable, so what will happen for the rest of the winter, next spring and next fall is impossible to predict.
But what is likely, he said, is that this virus will continue to cause illness for some time yet.
"Essentially, this virus will be around until it has affected everybody who is susceptible," he said from Ottawa Tuesday.
"Not everybody will get it, but everybody who is potentially able to get it eventually will get it, or be protected by the vaccine."
Numbers released by the Public Health Agency of Canada show that H1N1 activity in Canada has been falling for four weeks straight. Hospitalizations, ICU admissions and deaths have all dropped from the peak in early November.
The agency's weekly update, FluWatch, says the number of people in Canada reporting influenza-like illnesses to their doctors is now even below the expected range for this time of the year.
Butler-Jones says while it seems flu activity is waning, "we're still seeing people getting sick with this virus."
"It's still circulating. It's not as common, we're not seeing ICUs filled up like we did a month and a half ago, but it is something that will continue to spread slowly," he said.
Flu pandemics typically have a few small waves of activity as the virus moves and finds pockets of people not yet protected.
Butler-Jones admits that if there are future waves, they won't be as dramatic as what we saw this fall because so many people have already been immunized.
About 40 per cent of Canadians have gotten the vaccine and another portion has gained natural immunity after becoming sick with the virus, though the size of that proportion is not clear. But Butler-Jones says that doesn't mean Canadians should think they no longer need the vaccine.
"It's not too late to be immunized because the virus will keep coming back. And if you're not immunized or if you're not immune because of having been sick already, this virus still has the potential to cause illness," he said.
It's still unclear whether the vaccine campaign can be labelled a success,. The second wave may not have been as severe as feared either because predictions were exaggerated or because public health campaigns were such a success.
"That's the nature of public health. It's hard to measure what you prevent," said Butler-Jones.
He notes that Canadians have responded to this pandemic by getting the vaccines, coughing into sleeves, washing hands, and staying home when sick. "Now we can't say for sure that it's related to this, but we've seen a dramatic decrease in other infections and we think it's probably because of people doing the right things," he said.
He added that any death and any needless hospital admission are tragic.
But considering what it could have been, the work at all levels -- governments, individuals, etc. -- really has made a dramatic difference.
"And Canadians should be very proud of that."
