08 March 2010

Back away from the Purell

Slate | Darshak Sanghavi | How To Sell Germ Warfare: Can hand sanitizers like Purell really stop people from getting the flu?

Yet the data tell a less compelling story about sanitizers like Purell. In 2005, Boston-based doctors published the very first clinical trial of alcohol-based hand sanitizers in homes and enrolled about 300 families with young children in day care. For five months, half the families got free hand sanitizer and a "vigorous hand-hygiene" curriculum. But the spread of respiratory infections in homes didn't budge, a result that "somewhat surprised" the researchers. A Columbia University study also found no reduction in common infections among inner-city families given free antibacterial hand soap, detergent, and cleaning supplies. The same year, University of Michigan epidemiologist Allison Aiello summarized data on hand hygiene for the FDA and pointed out that three out of four studies showed that alcohol-based hand sanitizers didn't prevent respiratory infections. Then, in 2008, the Boston group repeated the study—this time in elementary schools—and threw in free Clorox disinfecting wipes for classrooms. Again, the rate of respiratory infections remained unchanged, though the rate of gastrointestinal infections, which are less common than respiratory infections, did fall slightly. Finally, last October, a report ordered by the Public Health Agency of Canada concluded that there is no good evidence that vigorous hand hygiene practices prevent flu transmission.
Hand sanitizer is one instance where identifying tends supported by people I don't trust and moving in the opposite direction has served me well. I've never bought the stuff, and my use of it is limited to things like after using port-a-johns while tailgating.  (Too much info? Probably.)

The article also mentions the man at the center of one of the more interesting stories from the philosophy of Science, Ignaz Semmelweis.
Why, then, do so many people think widespread use of hand sanitizers like Purell are the cornerstone of flu prevention? To be sure, hand-washing can save lives in medical settings. In 1847, Hungarian doctor Ignaz Semmelweis discovered that washing one's hands with chlorine between deliveries practically eliminated fatal infections among laboring women. (His colleagues ignored him and later committed him to a mental hospital, where he was beaten to death by guards.)

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