Sunday, October 18, 2009

The impact of flu vaccine hard to determine

From the Atlantic Monthly

Demonstrating the efficacy (or lack thereof) of vaccine and antivirals during flu season would not be hard to do, given the proper resources. Take a group of people who are at risk of getting the flu, and randomly assign half to get vaccine and the other half a dummy shot. Then count the people in each group who come down with flu, suffer serious illness, or die. (A similarly designed trial would suffice for the antivirals.) It might sound coldhearted, but it is the only way to know for certain whether, and for whom, current remedies actually work. It would also be useful to know whether vaccinating healthy people—who can mount an immune response on their own—protects the more vulnerable people around them. For example, immunizing nursing-home staff and healthy children is thought to reduce the spread of flu to the elderly and the immune-compromised. Pinning down the effectiveness of this strategy would be a bit more complex, but not impossible.

In the absence of such evidence, we are left with two possibilities. One is that flu vaccine is in fact highly beneficial, or at least helpful. Solid evidence to that effect would encourage more citizens—and particularly more health professionals—to get their shots and prevent the flu’s spread. As it stands, 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. The other possibility, of course, is that we’re relying heavily on vaccines and antivirals that simply don’t work, or don’t work as well as we believe. And as a result, we may be neglecting other, proven measures that could minimize the death rate during pandemics.

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