Improved handwashing at airports may reduce spread of infectious diseases: Study

Boston: Improving the rates of handwashing by travellers passing through just 10 of the world's leading airports could significantly reduce the spread of many infectious diseases, including the novel coronavirus, according to a study.

The greater the improvement in people's handwashing habits at airports, the more dramatic the effect on slowing the disease, said researchers, including those from the Massachusetts Institute of Technology (MIT) in the US. 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.

However, the study, published in the journal Risk Analysis, could apply to any such disease, and are relevant to the current outbreak, the researchers noted. People can be surprisingly casual about washing hands even in crowded locations like airports, they said. Travellers from different parts of the world are touching surfaces such as chair armrests, check-in kiosks, security checkpoint trays, and restroom doorknobs and faucets, the researchers said.

Based on data from previous research by groups, including the American Society for Microbiology, the team estimated that on average, only about 20 per cent of people in airports have clean hands -- meaning they have been washed with soap and water, for at least 15 seconds, within the last hour or so. The other 80 per cent are potentially contaminating everything they touch with whatever germs they may be carrying, the researchers said.

"Seventy per cent of the people who go to the toilet wash their hands afterwards," said Professor Christos Nicolaides from the University of Cyprus. "The other 30 per cent don't. And of those that do, only 50 per cent do it right," said Nicolaides, who is also a fellow at MIT. Others, he said, just rinse briefly in some water, rather than using soap and water and spending the recommended 15 to 20 seconds washing.

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 per cent of travellers in an airport have clean hands. Improving handwashing at all of the world's airports to triple that rate, so that 60 per cent of travellers to have clean hands at any given time, would have the greatest impact, potentially slowing global disease spread by almost 70 per cent, the researchers noted. Deploying such measures at so many airports and reaching such a high level of compliance may be impractical, they said.

However, the study suggests that a significant reduction in disease spread could still be achieved by just picking the 10 most significant airports based on the initial location of a viral outbreak. Focusing handwashing messaging in those 10 airports could potentially slow the disease spread by as much as 37 per cent, the researchers estimate.

They arrived at these estimates using detailed epidemiological simulations that involved data on worldwide flights including duration, distance, and interconnections. They also used the estimates of wait times at airports and studies on typical rates of interactions of people with various elements of their surroundings and with other people. Even small improvements in hygiene could make a noticeable dent, the researchers said.

The increasing prevalence of clean hands in all airports worldwide by just 10 per cent could slow the global rate of the spread of a disease by about 24 per cent, the researchers said. This could potentially be accomplished through education, posters, public announcements, and improved access to handwashing facilities, they said.

Numerous studies have shown that such measures can increase rates of proper handwashing, Nicolaides said. The researchers used data from previous studies on the effectiveness of handwashing in controlling transmission of disease. These data would have to be calibrated in the field to obtain refined estimates of the slow-down in spreading of a specific outbreak, the researchers said.

The findings are consistent with recommendations made by both the US Centers for Disease Control and the World Health Organization (WHO), they said. Both have indicated that hand hygiene is the most efficient and cost-effective way to control disease propagation, the researchers said.