Check Up: 'Hello' hygiene: Handshake or fist bump?

Adrian Monk, the obsessive-compulsive private detective now seen only in reruns, knew that handshakes could kill you. Medical researchers do, too: Hand hygiene is arguably the single most important area in hospital infection control.

So why do we - and doctors in particular - continue to shake hands?

Bacteriologically speaking, "the handshake is pretty gross," said Sara Mela, first author of a brief report in the American Journal of Infection Control last week that quantified that statement. "What other ways are there for greeting people?"

She and David E. Whitworth, both at Aberystwyth University in Wales, decided to compare contagion risks of handshakes, high fives, and fist bumps.

Mela, a doctoral candidate with a background in gut microbiology, first had to teach her coauthor how to fist bump, a gesture that many people discovered when Barack and Michelle Obama did it on the campaign trail in 2008.

But this was serious science.

The researchers were pretty sure, based on measurements of contact area using paint, that handshakes had the potential to transfer the most microbes and fist bumps the least. When they started testing real germs (E. coli) on gloved hands, they realized that handshakes were even more deadly.

Handshakes transferred twice as many bacteria (124 million, on average) as high fives, and 10 times as many as fist bumps.

"A handshake lasts much longer," explained Mela. And the grip is stronger.

What to do with this discovery is a far bigger challenge than the finding itself. Physicians, in particular, are instructed to shake hands with patients.

"You express yourself, you express empathy, you express a normal social life, when you are about to have an interaction" - a physical exam - "that is not normal social life," said Amy J. Behrman, medical director for occupational medicine at the Hospital of the University of Pennsylvania.

She was intrigued enough that she plans to raise the fist-bump idea at the hospital's next infection-control meeting.

Mark Sklansky, a professor at UCLA's David Geffen School of Medicine, is pretty clear that handshakes ought to be abandoned by the medical profession. But fist bumps would not be his first choice.

"If we can initiate a handshake-free zone," he said, "I would like people to have eye contact, smiles, maybe a gesture like putting a hand to your heart, something that shows warmth."

Pulling off such a cultural shift would be extremely difficult; handshakes date back at least to ancient Greece. A viewpoint Sklansky coauthored in May in the Journal of the American Medical Association ranks seventh in online attention out of 6,773 JAMA articles tracked by Altmetrics.

"It will take some time, but I think we can get there," he said. "Short of kissing, most things are going to be more appropriate than handshakes."

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