EpidemicsStudy: To Slow an Epidemic, Focus on Handwashing

By David L. Chandler

A new study estimates that improving the rates of handwashing by travelers passing through just 10 of the world’s leading airports could significantly reduce the spread of many infectious diseases. And the greater the improvement in people’s handwashing habits at airports, the more dramatic the effect on slowing the disease, the researchers found.

The findings, which deal with infectious diseases in general including the flu, were published in late December, just before the recent coronavirus outbreak in Wuhan, China, but the study’s authors say that its results would apply to any such disease and are relevant to the current outbreak.

The study, which is based on epidemiological modeling and data-based simulations, appears in the journal Risk Analysis. The authors are Professor Christos Nicolaides PhD ’14 of the University of Cyprus, who is also a fellow at the MIT Sloan School of Management; Professor Ruben Juanes of MIT’s Department of Civil and Environmental Engineering; and three others.

People can be surprisingly casual about washing their hands, even in crowded locations like airports where people from many different locations are touching surfaces such as chair armrests, check-in kiosks, security checkpoint trays, and restroom doorknobs and faucets. Based on data from previous research by groups including the American Society for Microbiology, the team estimates that on average, only about 20 percent of people in airports have clean hands — meaning that they have been washed with soap and water, for at least 15 seconds, within the last hour or so. The other 80 percent are potentially contaminating everything they touch with whatever germs they may be carrying, Nicolaides says.

“Seventy percent of the people who go to the toilet wash their hands afterwards,” Nicolaides says, about findings from a previous ASM study. “The other 30 percent don’t. And of those that do, only 50 percent do it right.” Others just rinse briefly in some water, rather than using soap and water and spending the recommended 15 to 20 seconds washing, he says. That figure, combined with estimates of exposure to the many potentially contaminated surfaces that people come into contact with in an airport, leads to the team’s estimate that about 20 percent of travelers in an airport have clean hands.