As governments around the world stockpile millions of doses of flu vaccine and antiviral medicines in anticipation of a potential influenza pandemic, two new surprising research papers published Thursday have found that many of the standard treatments now in use are far less effective than previously thought.
"The studies published today reinforce the shortcomings of our efforts to control influenza," wrote Dr. Guan Yi, a professor at the University of Hong Kong, in an editorial that accompanied the papers.
The two studies were published early online by the British medical journal the Lancet because of their important implications for the coming flu season.
In one paper, international researchers analyzed all the data from patient studies on the flu vaccine performed worldwide in the past 37 years, and discovered that the vaccine showed at best "a modest" ability to prevent infection with influenza or its complications in elderly people.
"The runaway 100 percent effectiveness that's touted by proponents was nowhere to be seen," said Tom Jefferson, lead scientist for the historical vaccine study.
Jefferson is a Rome-based researcher with the Cochrane Vaccine Fields project, an international consortium of scientists who systematically review research data.
"We were alarmed to find such a dramatic increase," said Dr. Rick Bright of the Centers for Disease Control in Atlanta.
He added, "Our report has broad implications for agencies and governments planning to stockpile these drugs for epidemic and pandemic strains of influenza."
Before 2000 almost no virus was resistant to the drug Amantadine.
During the first six months of 2005, 15 percent of the influenza-A viruses in the United States were resistant, up from 2 percent just one year before.
The immediate implications of these findings are most ominous for the developing world, because wealthier locations - European countries and places like the United States, Hong Kong, South Korea and Singapore - have been stockpiling newer, vastly more expensive antiviral medicines like Tamiflu, which are still on patent but are effective against the disease.
Even for wealthier countries, the research is alarming because it demonstrates how quickly and unexpectedly flu viruses can become impervious to medicines once the medicines are put into common use.
Called for comment, Dick Thompson, a spokesman for the World Health Organization, said that the agency could neither support nor deny the findings of the historical vaccine analysis, though he said some experts had criticized the researchers for "not including some important past studies" in their sample.
But the viruses' increasing resistance "is a finding that is being discussed widely within the flu world and will bear careful monitoring," he said, noting that he was not aware of any country in the developing world that had been able to stockpile the more expensive drugs.
The finding that flu vaccines have only a modest effect for the elderly is particularly worrisome, because that group tends to suffer high rates of complications and deaths from the disease, and vaccination is standard practice.
In people older than 65, the historical study said, the vaccines "are apparently ineffective" in the prevention of influenza, pneumonia and hospital admission, although they have reduced deaths from pneumonia by "up to 30 percent."
The best strategy to prevent the illness is to wash your hands."
The research showed, however, that vaccine offered better protection in nursing home patients, who suffered significantly lower rates of complications like pneumonia if inoculated.
Summarized by Copernic Summarizer