Does the flu vaccine help?
The flu vaccine protects against dying from the flu, right? “Of course,” I always assumed. Data superficially confirm that obvious assumption; people who get the flu vaccine are much less likely to die.
But the first rigorous study of whether the flu vaccine provides protection seems to show that people who get flu shots are less likely to die than those who don’t entirely because they’re healthier and live safer, according to a thought-provoking Atlantic article:
In 2004, Jackson and three colleagues set out to determine whether the mortality difference between the vaccinated and the unvaccinated might be caused by a phenomenon known as the “healthy user effect.” They hypothesized that on average, people who get vaccinated are simply healthier than those who don’t, and thus less liable to die over the short term. People who don’t get vaccinated may be bedridden or otherwise too sick to go get a shot. They may also be more likely to succumb to flu or any other illness, because they are generally older and sicker. To test their thesis, Jackson and her colleagues combed through eight years of medical data on more than 72,000 people 65 and older. They looked at who got flu shots and who didn’t. Then they examined which group’s members were more likely to die of any cause when it was not flu season.
Jackson’s findings showed that outside of flu season, the baseline risk of death among people who did not get vaccinated was approximately 60 percent higher than among those who did, lending support to the hypothesis that on average, healthy people chose to get the vaccine, while the “frail elderly” didn’t or couldn’t. In fact, the healthy-user effect explained the entire benefit that other researchers were attributing to flu vaccine, suggesting that the vaccine itself might not reduce mortality at all. Jackson’s papers “are beautiful,” says Lone Simonsen, who is a professor of global health at George Washington University, in Washington, D.C., and an internationally recognized expert in influenza and vaccine epidemiology. “They are classic studies in epidemiology, they are so carefully done.”
The results were also so unexpected that many experts simply refused to believe them. Jackson’s papers were turned down for publication in the top-ranked medical journals. One flu expert who reviewed her studies for the Journal of the American Medical Association wrote, “To accept these results would be to say that the earth is flat!” When the papers were finally published in 2006, in the less prominent International Journal of Epidemiology, they were largely ignored by doctors and public-health officials. “The answer I got,” says Jackson, “was not the right answer.”
The Atlantic article offers further evidence that sheds doubt on the flu vaccine’s effectiveness:
In 2004, for example, vaccine production fell behind, causing a 40 percent drop in immunization rates. Yet mortality did not rise. In addition, vaccine “mismatches” occurred in 1968 and 1997: in both years, the vaccine that had been produced in the summer protected against one set of viruses, but come winter, a different set was circulating. In effect, nobody was vaccinated. Yet death rates from all causes, including flu and the various illnesses it can exacerbate, did not budge. Sumit Majumdar, a physician and researcher at the University of Alberta, in Canada, offers another historical observation: rising rates of vaccination of the elderly over the past two decades have not coincided with a lower overall mortality rate. In 1989, only 15 percent of people over age 65 in the U.S. and Canada were vaccinated against flu. Today, more than 65 percent are immunized. Yet death rates among the elderly during flu season have increased rather than decreased.
News reports have spotlighted the “Swine Flu” as especially dangerous because — unlike “normal” flus — it supposedly kills many young, healthy people. But facts suggest that’s not true either:
As of August 8, only 36 deaths from swine flu had been confirmed among children in the U.S., and the overwhelming majority of those children had multiple, severe health disorders.
The article explains that young, healthy people’s immune systems put up a strong fight against flu, even without vaccination. And old, sick people’s immune systems don’t benefit much from vaccination because their immune systems don’t respond very well. This is, in theory, a reasonable explanation why flu vaccines may provide little benefit.
The scientific way to prove or disprove the flu vaccine’s effectiveness is a random experiment, in which some people are given the vaccine and others receive a placebo. But the scientific community seems to feel that — because the vaccine has “proven” its effectiveness — giving placebos would be unethical. Epidemiologist and flu expert Thomas Jefferson argues the exact opposite: “We have built huge, population-based policies on the flimsiest of scientific evidence. The most unethical thing to do is to carry on business as usual.”
Also interestingly, despite the inexplicable scientific consensus that flu vaccines work, “more than 50 percent of health-care workers say they do not intend to get vaccinated for swine flu and don’t routinely get their shots for seasonal flu, in part because many of them doubt the vaccines’ efficacy.” If many nurses and doctors — who could easily get vaccinated — tune out the flu vaccination hype and skip vaccination, isn’t a scientific study long overdue?
Posted by James on Wednesday, October 21, 2009