Thursday, October 08, 2009

Does last year's seasonal flu vaccine make us more susceptible to this year's H1N1?

I've heard quite a bit of noise about this unpublished Canadian study, but an independent blog has the best summary I've read. Emphases mine ...
Is the seasonal flu vaccine associated with H1N1 pandemic influenza? |

... The Canadian data appear to suggest that people who had been vaccinated against last year’s seasonal flu were about twice as likely as others to catch the pandemic strain when it appeared this spring.

But the CDC said U.S. data do not show a similar risk...

... “We continue to urge people to receive both the seasonal flu vaccine and the 2009 H1N1 vaccine,” Quimby said.

Likewise, an official of the World Health Organization said that investigators in countries other than Canada had not found a similar risk increase when they looked at their own data...
Note they're talking about last year's seasonal flu vaccine, not the vaccine my family received 2-3 weeks ago. I'd have found this more persuasive if they were talking about this year's seasonal flu vaccine.

I'm betting the BC researchers got this one wrong. Keith, I'll bet $10 for donation to a good cause :-).

Nov 20/2009: Later research suggests last year's seasonal flu vaccine protects against this year's H1N1. Looks like my skepticism was justified.

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