Officials with the Centers for Disease Control and Prevention say their flu vaccine may not be especially effective this year – and while the Canadian vaccine is slightly different than the American one, the same concerns are being felt north of the border.
Flu vaccines are modified each year based on what medical experts expect to be that season’s dominant strain of influenza.
The American vaccine contains two ‘Type A’ strains of the virus, as well as two ‘Type B’ strains.
The Canadian vaccine contains the same two ‘Type A’ strains, but only one ‘Type B’.
It’s one of the ‘Type A’ strains – H3N2 – that has officials in both countries warning of the potential for a relatively ineffective vaccine this year.
"Though we cannot predict what will happen the rest of this flu season, it's possible we may have a season that's more severe than most," Dr. Tom Frieden, director of the CDC, said Thursday at a news conference.
H3N2 – generally considered one of the most severe strains of the flu – is always included as part of the recipe for influenza vaccines.
After production began on this year’s vaccine, health authorities noticed that a new and different strain of H3N2 had appeared.
That new strain has, to this point, been found in about 48 per cent of influenza samples sent for lab analysis in the United States.
Still, officials expect the vaccine to provide some level of protection and urge people to get flu shots.
Public health officials in Waterloo Region say five lab-confirmed cases of influenza have been experienced thus far this season.
With files from The Associated Press
