How Good Is Your Flu Shot?

The annual flu-season ritual has begun again. First you will be admonished to get your flu shot.
Then you will be scared by reports of influenza outbreaks all around the nation.
The trouble is that it isn’t clear whether flu shots make much difference. A recent analysis in the British Medical Journal (Oct. 28, 2006) casts doubt on the effectiveness of flu shots, especially for the elderly.
Dr. Tom Jefferson is a vaccine epidemiologist who has reviewed all the influenza research and concluded that it leaves a lot to be desired. He notes that, “in healthy people under 65 vaccination did not affect hospital stay, time off work, or death from influenza and its complications.��?
Public health officials might argue that healthy younger people are not the primary target for flu shots. It is the older, more vulnerable population that is most at risk of serious complications or death from influenza, so they should benefit more from vaccination.
Unfortunately, the statistics don’t support this assumption either. Over the last three decades the death rate from flu in older people hasn’t changed much despite the fact that many more senior citizens are being vaccinated. Scientists reviewing these data concluded that flu shots don’t protect older, more susceptible people very well (Archives of Internal Medicine, Feb. 14, 2005).
Another analysis of flu vaccine effectiveness leads to the conclusion that flu shots are approximately 23 percent effective for elderly people in nursing homes (Lancet, Oct. 1, 2005). One might assume that those outside of nursing homes would fare better, but according to the scientists, “In elderly individuals living in the community, vaccines were not significantly effective against influenza, influenza-like illness, or pneumonia.��?
The public is sometimes suspicious of flu shots, claiming that they may give people flu-like symptoms. There is no evidence that this happens, but when it comes to vaccine safety the studies are unexpectedly scarce. According to Dr. Jefferson, there’s not much data on this score: “Although there appears to be no evidence that annual revaccination is harmful, such a lack of knowledge is surprising.��?
We’re not suggesting that people should skip their flu shots this year, but we do think more research is needed. Physicians pride themselves on practicing evidence-based medicine. Many would be shocked to discover that the science supporting influenza vaccination is so inadequate. We need better studies that prove flu vaccines are effective, especially in older people.
What alternatives do patients have? Some may wish to discuss antiviral flu medicine with their physicians. The evidence on these drugs is also imperfect, but they seem to speed recovery if taken early enough.
The Centers for Disease Control and Prevention says that older flu drugs like amantadine and rimantadine “are approximately 70 percent to 90 percent effective in preventing symptoms of influenza A illness.��? Newer medications such as Tamiflu or Relenza also seem to provide some protection, perhaps with fewer side effects.