Preventive Medicine Column
Dr. David L. Katz
‘Tis the season (at least here in New England) for apple picking, county fairs, pumpkins, and a seasonal brew of recommendations, fulminations, recriminations, allegations, and generalized befuddlement regarding the flu vaccine. What to do, this year, about flu?
That is, indeed, the punch line for most of us- but the road to that conclusion runs anything but straight. Let’s travel it together.
Among the road blocks, there are, for starters, the numerous conspiracy theorists –highly loquacious in cyberspace- who contend not only that flu vaccination is overtly dangerous, but that there is a systematic effort to delude the public about those dangers. Even readers who are not entirely convinced that the CDC is genocidal in its recommendation that everyone over 6 months of age be vaccinated (http://www.cdc.gov/flu) are given pause by such allegations.
One good reason for this hesitation is that for a vaccine to do you any good, you need to get it while feeling fine. This is quite different from, say, an operation that is much more dangerous- but easily justified by the obviously broken limb, plugged up gall bladder, or occluded arteries. It can be hard to talk yourself into rolling up your sleeve and getting jabbed with a needle while feeling fine even if you are not particularly worried about a government conspiracy. With a little nudge from conspiracy theories, however unreliable the source – doubt can become insurmountable.
The truth, though, is that influenza vaccine is many times- MANY times- safer than the flu itself. That does not mean flu is a plague, nor that the vaccine is perfectly safe. Nothing in medicine and little in life is perfectly safe. Harm from the flu vaccine is possible, but a highly remote risk. For what it may be worth to make this personal, I readily accept that ‘risk’ every year- for myself, my wife, and my children. I put the arms of my loved ones where my mouth is on this topic.
There are several reasons why the potential harms of flu vaccine may loom much larger in the imagination than they actually are. First, any adverse event- an allergic reaction, the now exceedingly rare case of Guillain-Barré syndrome- is amplified many orders of magnitude by repetition in the blogosphere. One case, appearing on 500,000 websites, exerts the influence of 500,000 cases.
But at least as important, we are generally blasé about risks that lack the intrigue of conspiracy. So, for instance, consider if flu infects one person in 5, and kills one person per 10,000 infected. There is certainly a good chance you, if healthy, would not be among those who get the flu. There is a very good chance the majority of people you know would not get the flu, either. And you are very unlikely to know anyone who is killed by flu.
But one infection per five means 60 million or so infections nationally. One death per 10,000 of these infections might be invisible in your circle of friends and family, but it would mean 6,000 deaths nationwide. This is consistent with a quite mild flu season in the U.S.
In contrast, the most dangerous flu vaccine in history- the notorious swine flu debacle 1976- was associated with 25 deaths. That’s bad- but it is more than two orders of magnitude less bad than even a mild flu season.
I realize, despite the cold hard facts, that there is something about immunization that just makes people nervous. Consider this, though: among the bloggers and pundits who propagate this anxiety, there are very few who have ever experienced polio or smallpox. Vaccine apprehension is largely a luxury enjoyed by societies no longer ravaged by the dreadful diseases vaccines have helped prevent.
Perhaps a more legitimate roadblock is doubt about the effectiveness of the flu vaccine. It is certainly far from perfect, and the elderly- who most need protection- may need two inoculations to get it. But leaving aside some of the subtleties that complicate measuring vaccine effectiveness in real-world settings, and applying even a low level estimate of overall vaccine effectiveness, routine flu vaccination produces a decisive overall benefit compared to just taking our chances with the flu.
Finally, we must recognize that when it comes to contagion, no one is an island. While true that the elderly most need protection and benefit least from vaccination, there is another way to protect our older loved ones: vaccinate ourselves. People who can’t get the flu can’t transmit the flu to those most vulnerable to it and its complications.
Which brings us to the literal and figurative bottom line we began with at the top: get vaccinated.
Dr. David L. Katz; www.davidkatzmd.com