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Canadian study suggests flu vaccine halves risk of infection this year
By Helen Branswell, The Canadian Press
January 16, 2013 7:30 AM
"It seems that this vaccine is cutting your risk of influenza in half, which ... is still important protection, especially if you're a high-risk person," said Dr. Danuta Skowronski, a flu expert with the British Columbia Centre for Disease Control who oversees the surveillance network from which the data was drawn.
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The U.S. CDC released interim vaccine effectiveness estimates late last week. In their analysis, this year's vaccine reduces the risk of requiring medical help for flu by 62 per cent overall, and by 55 per cent for influenza A viruses.
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The B component of the vaccine appears to be offering better protection this year than the A, about 70 per cent. And because the U.S. sample had such a large proportion of B cases, that had the effect of raising the overall estimate, Skowronski said.
But the Canadian figures are a closer representation of the proportion of A versus B viruses that are causing illness this winter in this country, she said. So far this flu season H3N2 has been responsible for the lion's share of Canada's cases.
In the interim analysis, 90 per cent of the positive cases were infected with influenza A and 10 per cent were infected with influenza B.
The A component of the vaccine appears to reduce one's risk by between 45 and 50 per cent, Skowronski said. There were too few B cases to calculate a reliable estimate, and the overall estimate for the flu shot was 47 per cent.
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http://www.edmontonjournal.com/healt...758/story.html
By Helen Branswell, The Canadian Press
January 16, 2013 7:30 AM
"It seems that this vaccine is cutting your risk of influenza in half, which ... is still important protection, especially if you're a high-risk person," said Dr. Danuta Skowronski, a flu expert with the British Columbia Centre for Disease Control who oversees the surveillance network from which the data was drawn.
...
The U.S. CDC released interim vaccine effectiveness estimates late last week. In their analysis, this year's vaccine reduces the risk of requiring medical help for flu by 62 per cent overall, and by 55 per cent for influenza A viruses.
...
The B component of the vaccine appears to be offering better protection this year than the A, about 70 per cent. And because the U.S. sample had such a large proportion of B cases, that had the effect of raising the overall estimate, Skowronski said.
But the Canadian figures are a closer representation of the proportion of A versus B viruses that are causing illness this winter in this country, she said. So far this flu season H3N2 has been responsible for the lion's share of Canada's cases.
In the interim analysis, 90 per cent of the positive cases were infected with influenza A and 10 per cent were infected with influenza B.
The A component of the vaccine appears to reduce one's risk by between 45 and 50 per cent, Skowronski said. There were too few B cases to calculate a reliable estimate, and the overall estimate for the flu shot was 47 per cent.
...
http://www.edmontonjournal.com/healt...758/story.html