Skepticism about science and medicine

In search of disinterested science

Public health and individual health

Posted by Henry Bauer on 2014/09/19

Recent posts about vaccines point to an inevitable conflict between public policy and individual autonomy. The risk can be greatly diminished of epidemics capable of sickening and even killing many people, but the price is the induced sickness and even death of a few individuals.

One anecdote in the NOVA program featured a lad who was crippled by polio contracted through vaccination by the oral polio vaccine. Despite his own sad experience, he was shown supporting the principle and practice of vaccination nevertheless. “Only” 2 or 3 in a million people experience this misfortune. An “expert” pointed out that as a result of this unfortunate case, it was realized that the less dangerous injected vaccine should supplant the oral one, “showing that the system worked”. He also mentioned that since the only cases of polio reported for many years had been those actually caused by the oral vaccine, clearly more attention ought to have been paid to making the vaccine as safe as possible. In other words, the system did NOT work — it took some personal tragedies for the system to do something that rationality could have foreseen the need for.

Yet no matter how well “the system” might work, the fundamental conflict remains: some unknown number of individuals, albeit a small number, will be harmed by actions that (are believed to) decrease risk for a large number of others. “Are believed to” to emphasize that one cannot in fact know that risk is being decreased in the case of diseases that have essentially disappeared in developed countries: If the risk of polio in the USA is 1 in a million from vaccination, what is the risk — if not vaccinated — of actually getting polio from an infected traveler from some other country? The cited experience of many years indicates that risk to be less than 1 in a million. Not vaccinating against polio may be less risky than vaccinating, apparently?

That point is easy enough to see when it comes to vaccines. Perhaps surprising, though, is that the same point applies to the use of clinical trials in the developing of drugs. Clinical trials can only gauge average effects, and it is far from obvious that all individuals should be treated according to such average results. This issue is argued in great detail in David Healy’s Pharmageddon (University of California Press, 2012).  For a short discussion, see my just-published “Clinical trials with surrogate outcomes have brought bad medicine(s)” .

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