Health Team

One flu bug has learned to ignore antiviral drug

Posted March 10, 2009

With the flu, symptoms generally are miserable and can become severe, and even life-threatening.

There are antiviral medications that may help lessen the symptoms and the duration of the bug if you take them within 48 hours of the first symptoms. But, one strain of the flu virus has become resistant to a commonly used antiviral drug.

flu shot Vaccination is key in avoiding flu

Right now, we're in the peak of flu season, a time when the federal Centers for Disease Control and Prevention analyze influenza samples sent to its Atlanta headquarters from across the country.

There, doctors “use the information we obtain from them to tell us whether or not they're related to the influenza vaccine strain,” said Dr. Alicia Fry.

Researchers have noticed a distinct change in how one strain of the illness – called Influenza A (H1N1) – has become resistant to a common antiviral drug called oseltamivir.

“Last year, about 12 percent of the Influenza A H1N1 viruses were resistant to oseltamivir, and this season it looks like approximately 98 percent – almost 100 percent – of those viruses are resistant to oseltamivir,” Fry said.

The study, reported in the Journal of the American Medical Association, compared patients who had flu caused by an oseltamivir-resistant virus with those cases that were not resistant to the drug.

None of the patients took the antiviral medication before infection, so the resistance was not related to that.

“We found out that their illness was very similar to illness with an oseltamivir-susceptible virus, so there was no difference in infection,” Fry said.

In the end, when it comes to the flu, experts say prevention with a vaccination is key.

“Certainly, the current influenza vaccine is effective against this oseltamivir-resistant H1 strain,” Fry said.

That’s good news for those who have had a flu shot and a little motivation for those who haven't.


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  • DontAnnoyMe Mar 11, 2009

    "Now where did I put that can of lysol?"

    Go ahead and use that lysol, sanitizing soap, and all that stuff. All you're doing is decreasing your natural immunity and giving the viruses another picnic site. Instead, start eating right and take tons of Vitamin D.

  • scientistjo Mar 11, 2009

    Charlesboyer...I suppose if they'd said "evolved" people would be all up in arms over that word. So they dumbed it down a lot. Personally, I liked being told that 98% is nearly 100% in this article. :)

  • jdragonflie Mar 11, 2009

    The flu is really bad right now, we were in the doctors office and the majority of the kids in there were walking out diagnosed with the flu. My daughter has the flu, and have 2 other daughters, and the flu is also being combined with strep throat, lots of fun at my house. Now where did I put that can of lysol?

  • charlesboyer Mar 11, 2009

    The bug has not "learned" so much as the drug culled the weaker of the species while the strong survived. Now, that subset has become dominant within the group.

    It's called "natural selection" and happens in nature every day. Instead of anthropomorphizing single cell pathogens and ascribing intelligence to them that they do not have, the article should point that simple truth out.