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Let Me See You Wash Your Hands!—A Commentary by Ian Ayres ’86

The following commentary was posted on nytimes.com on November 11, 2009.

Let Me See You Wash Your Hands!
By Ian Ayres ’86

One of the heroes of SuperFreakonomics is Ignatz Semmelweis — who crunched numbers in the 1840’s to champion the benefits of doctors washing their hands.

(I’ve written a bit about him myself and, for some odd reason, I just love to pronounce “Ignatz” out loud.) It has taken the medical profession a long, long time to get religion on hand sanitization.

But there is good news: Clean Hand programs are now the norm at hospitals. SuperFreakonomics explains how hand-hygiene compliance at Cedars-Sinai Medical Center “shot up to nearly 100 percent” after the hospital started using disgusting pictures of the bacteria found on the palm prints of physicians as screensavers. I can verify that other hospitals are copying this solution. A couple of weeks ago, one of my coauthors had a health scare and was hospitalized for a night in New Haven. Her hospital ward was plastered with color photocopies of disgusting, bacteria-laden palm cultures.

I’m also impressed with the increasing practice of hand-sanitation in front of the patient. Many health care workers show you that they have just applied Purell as they are coming in to examine you. We’re slowly getting to the point where patients might start calling out doctors who don’t sanitize in their presence. Indeed, in addition to the disgusting hand cultures, hospitals might do well to post notices asking patients to challenge anyone who tries to treat without sanitizing in their presence. (This idea is a bit like the restaurants that say “your food is free if you are not given a receipt.”)

The reason why unusual interventions are necessary is simply because voluntarism wasn’t working. Giving health care workers the unaided choice resulted in too many people bypassing the hand-washing opportunity. Sadly, hand sanitation is a classic non-durable precaution. To be effective, it needs to be done repeatedly. Psychologically, it needs to become routine for us to have a chance of making the practice stick. (That’s how I finally got in the habit of using a seat-belt.)

Having won the day with hospitals, we should turn our attention toward schools. Sadly, most schools are at best stuck in voluntary regimes where students can wash their hands if they want to. My concern is that not enough students avail themselves of this option. Even if 80 percent regularly choose to sanitize (a pipe dream), the persistence of a recalcitrant 20 percent might undermine the public health benefits of sanitation.

Here’s a minibleg: If your school or place of business has public hand-sanitizers, I’d love to learn how often you have to refill the dispensers. If we know the rate of use and the number of people in the building, we can know the average rate of sanitation. I bet we’d find that the rate of sanitation would be very low. (I bet we’d find a similar result if we compared toilet paper use to soap use in school toilets. We should be very scared if there are 100 sheets of toilet paper used for every dose of hand soap.)

Schools should experiment with mandating routine, public hand sanitation. As a beginning, they might put Purell dispensers in science class and ask the teachers to make sure that their students dose their hands at the end of class.

Mandating hand-sanitation might reduce sick days by as much as 20 percent. In fact, that’s what this 2002 study of 18 elementary schools (located in Delaware, Ohio, Tennessee, and California) found. The study protocol required multiple sanitations per day:

[T]he students were instructed to also use the waterless alcohol gel hand sanitizer when entering and leaving the classroom, especially first thing in the morning, before and after lunch, after recesses, after use of the restroom, and before going home. Students were also encouraged to use the sanitizer when they sneezed or coughed.

Crucially, the study made teachers responsible for ensuring that the protocol was followed.

Compared with paired control group schools, students who were forced to clean their hands ended up with 19.8 percent fewer sick days (the full article is behind a firewall here; similar studies are abstracted here). And teachers’ absenteeism dropped by 10.1 percent. These figures ignore the beneficial effects on moms and dads and others who probably got sick less too.

As our nation suffers through another flu season, the spirit of Ignatz Semmelweis calls out to us across the decades for less discretionary hand sanitation.