Monday, December 22, 2014

Chandigarh has Bird flu cases, will taking the seasonal flu vaccine help?

Recently it has been reported that Chandigarh is having Avian Flu (Bird Flu H5N1) cases. 
I have received numerous calls and parents who have asked me whether they should take the Seasonal Influenza vaccine now, and whether it would prevent the Bird Flu disease?
Here is what I have found.
The short answer is NO, seasonal flu vaccine cannot directly prevent bird flu, since they are different strains of the same virus, against which the vaccine will not work.
However, the situation is a little bit more complicated than this
As per Wikipedia listing on prevention of bird flu
Notwithstanding possible mutation of the virus, the probability of a "humanized" form of H5N1 emerging through genetic recombination in the body of a human co-infected with H5N1 and another influenza virus type (a process called reassortment) could be reduced by widespread seasonal influenza vaccination in the general population. I"
And here is what the CDC has to say on this situation as well
CDC website "Seasonal influenza vaccination will not prevent infection with avian influenza A viruses, but can reduce the risk of co-infection with human and avian influenza A viruses. "

So here is what I conclude

Taking the Seasonal Influenza vaccine cannot directly prevent Avian Flu (H5N1), since they are antigenically different.
However, it can assist in a couple of situations
1. It can prevent co-infections with seasonal flu & bird flu together - kind of obvious since it will prevent seasonal flu.
2. It can thus help prevent a humanized form of bird flu virus happening, since if the bird flu virus and the seasonal flu together infect someone, they may exchange/ share their genes, leading to increased transmission of the bird flu disease to humans.
This is the basic rationale for doing flu vaccine in situations where bird flu exists.

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