In December 2019, just days before Christmas, an interesting study came out. The coronavirus cases were just starting to emerge, and the study mostly flew under the radar.

But the timing is remarkable considering the study’s conclusions: if you want to prevent or mitigate a pandemic, wash your hands — especially at airports.

30% don’t wash hands, and 35% don’t do it right

There’s a reason why the “wash your hands” advice gets thrown around so much in the time of the coronavirus outbreak. Well, there are two reasons, actually. The first one is that it works.

Our skin is essentially a protective armor, defending us from the endless stream of pathogens we encounter in our day to day life. Unless you cut yourself, viruses can’t really break through your skin. But there’s a chink in our armor (several, actually) — and they’re mostly on our face.

Our mouth, nose, and eyes, are excellent gateways pathways for pathogens to enter our body. The problem isn’t just that they can be exposed to pathogens directly, but we often bring pathogens there ourselves. Remember how we said your skin is effective at keeping stuff outside of you? Well, it keeps them outside, but it doesn’t really kick them out. The pathogens may not be able to enter your body, but they stay on your skin for a while. Every time you touch your face, you increase the chance of infection.

A 2015 study found that on average, we touch our face an average once every 2-3 minutes, and 44% of that touching involves contact with eyes, nose or mouth. Washing your hands is by far the best way to make sure we don’t push pathogens towards our vulnerable areas.

The second reason why health professionals keep telling us to wash our hands is that, well, we don’t really do it enough.

Previous research has found that up to 30% of airport travelers don’t wash their hands after going to the bathroom — and that’s an optimistic figure overall because some airport travelers might not go to the toilet at all (and not wash their hands).

Then, out of the 70% who do wash their hands, “50% don’t do it right”, says Prof. Christos Nicolaides, who has published the above mentioned 2003 study on hand washing in airports.

Why airports?

Air travel is particularly important in any outbreak. It’s how the disease spreads from one community to the other, which makes it extremely difficult to track and contain the disease. This is exactly what has happened to Covid-19: hopes that the disease would be contained in China were disproved and now, several countries are having their own disease clusters in different geographical areas (Italy, South Korea, Iran).

As if that wasn’t enough, airports themselves are hotspots for diseases. They’re full of crowded people from all around the world and are often surprisingly unhygienic.

The 2019 study starts thusly:

“The risk for a global transmission of flu‐type viruses is strengthened by the physical contact between humans and accelerated through individual mobility patterns. The Air Transportation System plays a critical role in such transmissions because it is responsible for fast and long‐range human travel, while its building components—the airports—are crowded, confined areas with usually poor hygiene.”

So far, nothing new. But what the study found is that by increasing air travelers engagement with hand washing, a potential pandemic “can be inhibited by 24% to 69%” — that’s right, the lion’s share of a global pandemic can be cut down if we’d simply wash our hands at airports.

“Our results provide evidence for the effectiveness of hand hygiene in airports on the global spread of infections that could shape the way public‐health policy is implemented with respect to the overall objective of mitigating potential population health crises,” the study concluded. Just imagine what we could achieve if we’d wash our hands everywhere — even when there’s not a pandemic.

Particularly good against the novel coronavirus

The study doesn’t mention the coronavirus in any way (it came out before the outbreak took shape), but its findings apply excellently to the current situation.

In the case of Covid-19, perhaps it’s even more effective than in other pathogens.

Coronaviruses in general (not just the novel one) are enveloped viruses, which means that they have an outer lipid membrane layer. Simply put, coronaviruses are surrounded and protected by a layer of fat.

This makes them one of the easiest viruses to kill with the appropriate disinfectant product. Furthermore, even washing your hands with soap — which usually doesn’t kill pathogens as much as it gets them away from your skin — can kill coronaviruses. The soap can dissolve the fatty layer and kill the virus. You just need to wash your hands long enough (20 seconds), and you’re good to go.

The 20 seconds part is important. To make sure you wash your hands for the right amount of time, 20 seconds is the amount of time it takes to sing “Happy Birthday” twice — or just think of any chorus that’s stuck in your head, singing it twice should be a good timekeeper.

Of course, in our day to day life, we can spend hours without having access to a place to wash our hands. Fret not — sanitizers also work. Just make sure they have an alcohol content of 60% or over, and that will also do the job (as long as you cover your hands thoroughly).

In addition to ensuring you wash your hands for 20 seconds, here’s what you need to do for a proper handwashing:

• make sure you use enough soap to cover your hands on both sides;
• rub your hands together, using one hand to clean the other;
• clean between your fingers, on both sides;
• pay attention to your thumb, clean it carefully;
• rub the tips of your fingers on the palm of your other hand. Do the same with the other hand;
• rinse your hands thoroughly;
• dry your hands (preferably with a disposable towel).

There you have it, the most powerful weapon against a pandemic. All it takes is 20 seconds, several times a day.