NCPA - National Center for Policy Analysis


September 26, 2005

As governments stockpile millions of doses of flu vaccine and antiviral drugs in anticipation of a potential influenza pandemic, two separate studies found such treatments are far less effective than previously thought.

  • International researchers discovered that vaccines showed at best a "modest" ability to prevent influenza or its complications in elderly people, although vaccines did reduce deaths from pneumonia by up to 30 percent.
  • The Centers for Disease Control and Prevention found influenza viruses, particularly those from the bird flu strain, had developed rates of resistance to the only class of cheap antiviral drugs available; these resistance rates have increased rapidly since 2003, particularly in Asia.

The vaccine study showing inoculations have only a modest effect in the elderly is particularly worrisome, since this group tends to suffer high rates of complications and deaths from influenza, say researchers.

Rick Bright of the disease control centers says their report has broad implications for agencies and governments planning to stockpile antiviral drugs for epidemic and pandemic strains of influenza:

  • Before 2000, almost no virus was resistant to the drug Amantadine, but by 2004, 15 percent of influenza A viruses collected in South Korea, 70 percent in Hong Kong and 74 percent in China were impervious.
  • During the first six months of 2005, 15 percent of the influenza A viruses in the United States were resistant, up from 2 percent the year before.
  • All human cases of the bird flu A(H5N1) strain -- which is still extremely rare in humans -- have been resistant.

Many find the research alarming because it demonstrates how quickly and unexpectedly flu viruses can become impervious to medicines once they are put into common use, as they would in the case of a pandemic.

Source: Elisabeth Rosenthal, "2 Studies Find Flu Treatments Fall Far Short," International Herald Tribune/New York Times, September 22, 2005.

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