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The Power of Hand-Washing to Prevent Coronavirus

03/18/2020 06:00AM | 1840 views

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The single most important piece of advice health experts can give to help us stay safe from COVID-19 is this one: Wash your hands.

“In the final analysis, it’s the hands. The hands are the connecting piece,” says Elizabeth Scott, PhD. Scott co-directs the Center for Hygiene and Health in Home and Community at Simmons University in Boston.

 

 

“You can’t necessarily control what you touch. You can’t control who else touched it. But you can look after your own hands,” she says.

Hand-washing -- with soap and water -- is a far more powerful weapon against germs than many of us realize.

Scott says it works on two fronts: “The first thing that’s happening is that you’re physically removing things from your hands. At the same time, for certain agents, the soap will actually be busting open that agent, breaking it apart.”

Coronaviruses, like this year’s version that has left 100,000 worldwide infected with COVID-19, are encased in a lipid envelope -- basically, a layer of fat. Soap can break that fat apart and make the virus unable to infect you.

The second thing soap does is mechanical. It makes skin slippery so that with enough rubbing, we can pry germs off and rinse them away.

Sounds pretty simple, but the vast majority of people still don’t do it right.

A 2013 study had trained observers discreetly watch more than 3,700 people wash their hands. It found that only about 5% of them followed all the rules. About one in four people just wet their hands without using soap -- a move hygiene researchers call the “splash and dash.” About one in 10 didn’t wash at all after a trip to the restroom. The most common shortcoming for most people was time. Only 5% spent more than 15 seconds washing, rubbing, and rinsing their hands.

Scott says that’s not good enough if you’re trying to keep from getting sick.

With a new virus on the loose, the stakes are higher now. It’s time to bring your technique up to speed.

 

 

How? Well, first turn on the water. It doesn’t matter if it’s hot or cold.

“We’ve done research on water temperature, and what we’ve discovered is that water temperature doesn’t really matter in terms of effectiveness,” says Donald Schaffner, PhD, who studies predictive food microbiology, hand-washing, and cross-contamination at Rutgers University in New Brunswick, NJ.

Second, lather up. The soap helps germs slip off your skin as you rub your hands together.

If you’re in control of the soap you’re using, you may want to pick a liquid or gel over foaming pump soap. A 2017 study that compared liquid and foam soaps from the same brand found that washing with foam didn’t significantly reduce bacteria on the hands of people who were in the study, while washing with a liquid soap did.

The study was small and the first of its kind. Generally, scientists like to see research results repeated before they are accepted as fact. Study participants only washed for 6 seconds. Sadly, that’s about the average time most of us spend washing our hands -- but it’s less than the 20 seconds the CDC recommends.

Still, study researchers think their results make sense. Because foam washes off more quickly than gel soap, users are more likely to splash and dash after a dollop of foam.

“People tend to wash their hands for a shorter duration with the foam soap,” says Ozlem Equils, MD, president of an educational nonprofit called MiOra.

What about bar soap? Numerous studies have found that bacteria can stay on bar soap that stays wet because it gets used frequently. But studies that have looked to see whether that’s a problem show that the bacteria don’t seem to transfer to the next user. If your bar looks slimy, rinse it off under water before you lather your hands, and try to store it so it will dry out between uses.

If you’re in a public bathroom, and there’s no soap, just rubbing your hands together under the water does do some good. A 2011 study from researchers at the London School of Tropical Hygiene found that washing with water alone reduced bacteria on hands to about one-quarter of their prewash state. Washing with soap and water brought bacterial counts down to about 8% of where they were before washing. 

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