What You Need to Know About H3N2

This year's flu virus, H3N2, seems to be particularly nasty, taking children out of school left and right and affecting everyone around it. However, what most people don't realize is that it's not the H3N2 virus that's wreaking havoc, but instead a drifted virus form of the virus, which may make sense of why your child was still affected by the flu even if he or she was vaccinated against it.

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The CDC says that 52 percent of the H3N2 viruses collected and analyzed in the United States from October 1 to November 22 were antigenetically different, or drifted, from the H3N2 component included in this year's flu vaccine. That means that the majority of the flu viruses going around are less protected by the flu vaccine, which was designed to protect against a different form of the H3N2. While 48 percent of the viruses collected and analyzed in the US were like the H3N2 vaccine component, that still leaves the majority of the viruses to be unlike the vaccine component.

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The CDC still recommends getting the flu vaccine, however, because it is still able to provide some protection against drifted viruses. "Though reduced, this cross-protection might reduce the likelihood of severe outcomes such as hospitalization and death," said the agency in its announcement. "In addition, vaccination will offer protection against circulating influenza strains that have not undergone significant antigenic drift from the vaccine viruses (such as influenza A (H1N1) and B viruses)."


If you or your child does contract the drifted flu virus this winter, you should administer neuraminidase inhibitor antiviral medications as soon as possible after the illness' onset. Prescription medications that are being used to treat the virus are oseltamivir (Tamiflu) and zanamivir (Relenza). Usually those prescriptions are recommended for anyone who is hospitalized, has a severe, complicated or progressive illness, or anyone who is at higher risk for influenza complications.

>> Read more: Can You Get Sick From A Flu Shot?