The inescapable grossness of that staggering statistic borders on being comical. But there's really nothing funny about it, considering people around the world die every day from infectious diseases that could be dramatically mitigated if only people bothered to practise good hand hygiene.
"Seventy percent of the people who go to the toilet wash their hands afterwards," says physicist and data scientist Christos Nicolaides from the University of Cyprus and MIT.
"The other 30 percent don't. And of those that do, only 50 percent do it right."
What are the real-life consequences of this abject failure to keep our hands clean? They're dire, new research from Nicolaides and his team suggests – particularly with regard to the way that contagion can rapidly spread throughout the world due to air travel, which has the power to turn epidemics into pandemics, and frighteningly quickly.
That's something health authorities around the world are desperately trying to prevent right now in the grim midst of the Wuhan coronavirus. And it's something we can help with, the new study finds, if only people washed their hands better at airports.
Previous research has demonstrated that as few as one in five people in airports have clean hands at any given moment, meaning they've washed their hands with soap and water, for at least 15 seconds, within the last hour.
That's a pretty huge problem, given the vast number of things people touch with their hands in airport environments, including trays, railings, touch panels, doors, and much more.
Using epidemiological modelling and Monte Carlo simulations, the researchers calculated that increasing the amount of people with clean hands in airports would significantly lower the transmission of infections, lowering the likelihood of epidemics turning into pandemics.
"Our simulation results suggests that, if we were able to increase the level of hand cleanliness at all airports in the world from 20 percent to 30 percent … a potential infectious disease would have a worldwide impact that is about 24 percent smaller," the authors write in their study.
"Increasing the level of hand cleanliness to 60 percent at all airports in the world would have a reduction of 69 percent in the impact of a potential disease spreading."
Even though we should all be washing our hands already (and should know the importance of it), the authors acknowledge that due to reasons of practicality and cost, it wouldn't be easy to quickly ramp up hand hygiene practice and awareness in all airports.
But the study also looked at the hypothetical effects of improving hand cleanliness at just the 10 most pivotal airports in the world for reducing infection transmissibility. Even if hand-washing was only increased at those 10 locations, disease spreading would decrease significantly, from 45 percent to 37 percent.
The researchers acknowledge their estimates involve numerous limitations and assumptions that may not accurately reflect real-life infection transmission, but hope their findings may encourage health authorities and decision-makers to consider the case for simply increasing the promotion of hand-washing in airports.
"[It] could help hindering any infection within a confined geographical area during the early days of an outbreak, inhibiting its expansion as a pandemic," the researchers say.
"Population engagement with proper hand hygiene could be a simple and effective solution for preventing transmission of infections and reducing the risk of massive global pandemics."
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