One Way To Slow An Epidemic

The COVID-19 Coronavirus is making news right now. The outbreak is spreading and is being felt physically, socially and financially across the globe. Authorities are working feverishly to stop the spread. But is one of the most fundamental disease prevention habits the real key to stopping the outbreak?

As it turns out, your mom might have had the key to halting this, or any number of other outbreaks. A basic hygiene habit that virtually every human on the planet can do.

Hand-washing. That’s it. Wash your hands, stop an outbreak.

More specifically, hand-washing at airports. Professor Christos Nicolaides of the University of Cyprus just led a study that found something very interesting. Improving the rates of hand-washing among travelers using just 10 of the world’s leading airports can significantly suppress the spread of infectious disease. The greater the improvement in hand-washing, the stronger the suppression of disease spread, according to the research team.

These results were published in December, prior to the outbreak of the novel Coronavirus COVID-19 in Wuhan, China (nicknamed the “Wu Flu” or “Kung Flu.”) They were dealing with infectious disease in general, but the researchers say their results apply across the board, including for flu and COVID-19.

The study was published in the journal Risk Analysis, and is based on epidemiological modeling and data-based simulations. The research team included Nicolaides, who is a fellow at MIT’s Sloan School of Management, Professor Ruben Juanes of MIT’s Department of Civil and Environmental Engineering and three others.

Humans touch thousands of surfaces each day, picking up biological hitchhikers in the process. Bacteria, viruses, fungus, microscopic insects and a myriad of other matter, both disease-bearing and benign, hang around on hands for hours, even days.

We’re often quite casual, even lazy about hand-washing, even in places where we should know better. Airports and other crowded, public locations provided a “multiplier effect” for the biological stuff we end up coming in contact with. Thousands of people touching thousands of surfaces – from chair armrests to security apparatus to bathroom fixtures – then coming together in a sort of “perfect storm” of biological exchange, sharing all they are carrying with everyone who touches the surfaces they touch.

It’s a wonder we’re not all dead already.

The human immune system is a wonderful and powerful thing, but the volume of biological “stuff” we are capable of contacting on any given day can easily overwhelm it. Hand-washing may be the difference maker in sparing our immune systems from the ravages of serious illness.

Yet according to earlier research by groups like the American Society for Microbiology, the MIT team estimates that only about 1 in 5 people in airports have clean hands. They define that term as meaning their hands had been washed with soap and water for at least 15 seconds and within the previous hour.

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The other 80 percent? They’re busy contaminating everything they touch with whatever virulent pathogens they might be carrying, says Nicolaides.

“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.

If hand-washing rates at the world’s airports could be improved to 60 percent, the global spread rate of disease could be slowed by nearly 70 percent, according to the researcher’s models. While doing this on a universal basis (every airport) may be a virtual impossibility, the team believes that it could be done at the 10 most significant airports, and that that could slow the global spread rate of disease by as much as 37 percent.

How did they come to that estimate? Their model included epidemiological simulations that took into account a variety of data on worldwide flights. It considered flight duration and distance, interconnections and wait times at airports. The model also took into consideration studies about typical rates of interactions between people and various elements of their surroundings as well as between people and other people.

Remarkably, the models indicated that even minor improvements in hygiene could significantly improve the spread rate of disease. Creating just a 10 percent increase in the prevalence of clean hands in airports around the world would slow the global disease spread rate by about 24 percent. The research team believes this could be accomplished by educating people, using media like posters and public announcements and by improving access to hand-washing facilities. Previous studies have shown that these measures can increase the rates of effective hand-washing, Nicolaides says.

“Eliciting an increase in hand-hygiene is a challenge,” he says, “but new approaches in education, awareness, and social-media nudges have proven to be effective in hand-washing engagement.”

In order to obtain more accurate and refined estimates of the rate of slow-down of global disease spread related to hand-washing, researchers would need to focus on a single, specific outbreak. They would require updated and specific data to relate the effectiveness of hand-washing to the slow of the disease spread rate. For this study, the team used previously collected and more generalized data, according to Juanes.

The U.S. Centers for Disease Control and Prevention, the World Health Organization and your mom have all made recommendations that match those of the research team in the past. The big-shot, government funded organizations also say that other things would be useful in stemming the spread of an outbreak. These include travel restrictions (yes, travel bans,) use of surgical masks and even airport closures.

But, like your mom, the CDC and WHO recognize that increased hand-washing and hygiene are the first line of defense against the spread of disease – and the most cost-effective and efficient tools in the war against raging pathogens. It’s also the simplest to implement.

The authors believe their study is the first to quantitatively gauge how effective something as simple as increased hand-washing rates would mitigate the risk of an epidemic or pandemic on a global scale. They point to the numerous studies done connecting better hand hygiene and better control of disease transmission between humans as being a good start, but not the kind of detailed, actionable model theirs represents.

A security officer uses a temperature gun to check people leaving Wuhan Tianhe International Airport in Wuhan, China, on Tuesday. (AP photo/Dake Kang)

While you might think the busiest airports would be the ones most responsible for spreading disease, but the researchers found something els. They named 120 airports that are most influential in disease spread. These included Tokyo and Honolulu, both of which have exaggerated impacts on disease spread not due to size or traffic, but based on their location.

Weighing in at 46th and 117th, respectively, in terms of size, their influence is multiplied because of the number of direct connections they have to the world’s biggest airports, the number of long-range international flights they service and their position right between the global East and West.

By identifying the 10 airports with the most impact on disease spread, the authors say, it gets easier to multiply the impact of increased hand-washing and hand hygiene. Once the source of an outbreak is located, finding the 10 closest to it and increasing hand-washing and hygiene there wold be the most effective way to limit the spread of the outbreak.

Nicolaides suggests that hand-washing rates and overall hygiene could be improved at airports if hand-washing stations were not restricted to just restrooms. Putting them in traffic areas might encourage those not using the restrooms to wash hands more often. He also suggests more frequent cleaning of the surfaces most frequently contacted by the largest numbers of people.

Want to stop the outbreak of deadly diseases? Apparently, you need to listen to your mom. Of course now she has a whole bunch of science to back up her motherly wisdom. Not that she ever needed it.

Keep the faith and keep after it!

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Material Source – Massachusetts Institute of Technology

Journal Reference – Christos Nicolaides, Demetris Avraam, Luis Cueto‐Felgueroso, Marta C. González, Ruben Juanes. Hand‐Hygiene Mitigation Strategies Against Global Disease Spreading through the Air Transportation Network. Risk Analysis, 2019; DOI: 10.1111/risa.13438

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