To curb the global spread of disease, one of the simplest actions turns out to be remarkably effective: washing your hands.
Tripling the number of people with clean hands at all airports – at most only about 20% of people at airports have clean hands – could curb pandemics by as much as 69%, according to a new study from MIT Sloan researcher Christos Nicolaides, SM ’11, PhD ’14 and his co-authors. The researchers found that increased hand-washing at just 10 key airports can drop the risk of a global pandemic by as much as 37%, though Nicolaides said airport washroom capacity may make that an unrealistic short-term goal. Co-authors on the paper include MIT professor Ruben Juanes and MIT research affiliate Luis Cueto-Felgueroso.
Nicolaides, a digital fellow with the MIT Initiative on the Digital Economy, and his colleagues used epidemiological modeling, data-driven simulations, global travel patterns and an analysis of effectiveness of hand-washing to study how airport hygiene could affect global spread of diseases. The paper, “Hand-Hygiene Mitigation Strategies against Global Disease Spreading through the Air Transportation Network,” appeared in December in the journal Risk Analysis.
Improving the level of hand cleanliness at airports from 20% to 60% could curb a pandemic by 69%.
Airports play a major role in spreading contagious diseases by bringing large numbers of people together in contained spaces with poor air ventilation and often poor hygiene. Travelers also come in contact with highly contaminated surfaces, from self-service check-in screens, water fountains, and door handles in the airport to seats and tray tables on planes.
Before air travel, contagious diseases like the Black Plague spread slowly, and rarely moved across continents. Air travel allows people to travel more often and much longer distances, which means diseases can spread quickly, too — like the coronavirus disease COVID-19, which begin in Wuhan, China and spread to other countries around the world.
As airports have the potential to turn a disease into a pandemic, public health officials could take drastic steps like diverting air traffic or shutting down airports. Smaller local measures like hand washing are simple, inexpensive, and effective, the researchers said. Washing hands with water and plain soap can significantly reduce bacteria contamination down to 8% from 44%, a 2011 study found. Increasing the amount of air travelers at all airports with clean hands to 30% can make the impact of a potential pandemic 24% smaller, the researchers found. (Methods of improvement include boosting awareness and increasing handwashing capacity.) Improving handwashing to the point where 60% of passengers have clean hands can reduce the impact of a potential pandemic by 69%.
At any given time, about 20% of people in airports have clean hands.
A more targeted approach includes improving handwashing at 10 key airports — London Heathrow, Los Angeles International, John F. Kennedy International in New York City, Charles De Gaulle in Paris, Dubai International, Frankfurt, Hong Kong International, Beijing Capital International, San Francisco International, and Amsterdam Airport Schiphol in Amsterdam— that are particularly likely to spread disease in general, or 10 airports that are close to the source of the particular outbreak. In those instances, the researchers found, global spread of disease could be reduced by anywhere from 8% to as much as 37%.
But drastically improving handwashing rates is a daunting undertaking, Nicolaides pointed out. “Increasing the percentage of people at airports with clean hands to 60% is quite difficult and maybe an infeasible task,” he said. “To achieve this level of hand cleanliness, almost 75% of people in an airport should be washing their hands within an hourly time window. Current washroom capacity cannot support this.”
The researchers defined proper hand-washing technique as using water and plain soap and scrubbing for at least 20 seconds, the amount of time recommended by the Centers for Disease Control.