Flu Shots May Not Protect Elderly

But researchers say seniors should get one anyway. Why?

The flu vaccine might not protect seniors as much as previously thought, according to a study of more than 3,500 patients over age 65 that found no link between flu vaccination and risk of pneumonia during three flu seasons.

One problem with previous studies looking at efficacy is that they failed to account for differences between healthier seniors and those who were 'frail,'" said lead researcher Michael Jackson, a postdoctoral fellow at the Group Health Center for Health Studies.

This study, published in The Lancet, used a rigorous case control method that included a control time period, after a flu vaccine became available but before each flu season actually started.
During those pre-flu season periods, people who had been vaccinated were much less likely to get pneumonia.

Why?

One possibility is the "healthy user" effect.

"Those who got the vaccine happened to be healthier--not because the flu vaccine was protecting them from pneumonia caused by the flu, since it wasn't present yet," Jackson said.
It's not the first study to point out that the use of flu vaccines in seniors might be a waste of time and money. A review by George Washington University researchers published in the Lancet Infectious Diseases found that flu shots may not save as many older patient's lives as generally claimed.

And a study led by Dean Eurich of the University of Alberta found that flu vaccinated people fared better than those without vaccination during the part of the year when influenza wasn't circulating. Once they adjusted for the "healthy user" effect, however, they found the benefit close to disappeared.

"So for several years now, we have had large studies which question the benefit of influenza vaccination. The notion that flu shots are so important thus seems more the result of repeated assertion than the weight of solid scientific evidence," said Peter Doshi, a graduate student at MIT, who was not involved in the Lancet study.

One of Doshi's studies, published in the May issue of the American Journal of Public Health, questioned the impact of influenza itself. Doshi suggests influenza is not as much of a problem as we have thought. Deaths from influenza have been consistently declining over the twentieth century, a trend that began far before the introduction of widespread vaccination, Doshi asserts.

Still, the researchers say the flu vaccine is safe so it seems worth getting, even if it might lower the risk of pneumonia only slightly.

"Despite our findings, and even though immune responses are known to decline with age, I still want my grandmother to keep getting the flu vaccine," said Jackson.

Doshi finds this troubling because it suggests there is an unspoken rule that "responsible scientists" must encourage vaccination, never question, discourage, or remain neutral, no matter what the evidence is.

"Such a taboo is irresponsible and definitely not serving the public's best interest," he said.
It also throws us back to the 1950s, the era of "the drug is safe, therefore let's use it," Doshi said. In 1962 the Food and Drug Administration required that drug manufacturers had to prove the effectiveness of their products before marketing them.