From JAMA, the journal of the American Medical Association.
The influenza virus continues to lay low any infectious disease experts who claim to truly understand it, as two articles and an editorial in JAMA recently showed.
One report from the CDC found that influenza A (H1N1) resistance to oseltamivir, one of the main drugs used to treat the virus, has zoomed from being uncommon in the 2006-2007 flu season, to 12% of cases being resistant in 2007-2008, to 98% being resistant among cases so far in this 2008-2009 flu season.
Experts used to think that the mutation that causes the virus to become resistant to oseltamivir made it less likely to cause illness or death. No such luck. The CDC report and another study from the Netherlands found that it maintains its virulence.
An even bigger shocker: Both studies also found that the influenza virus developed resistance irrespective of how much oseltamivir was used. The paradigm of antibiotic overuse leading to bacterial resistance doesn’t seem to apply to influenza virus and its treatments. “That, frankly, has caught us with our intellectual pants down. That really did surprise us,” said Dr. William Shaffner of Vanderbilt University, Nashville, who was not part of these studies.
A fourth article about influenza in the same issue contained a little ray of sunshine, however. Vaccination reduced the risk of getting the flu, even in healthy, fit, members of the U.S. military. With fewer effective treatments due to resistance, getting an annual flu shot makes more sense than ever. So next flu season, roll up your sleeve…