Why handwashing with soap is the most effective way to stop viruses

We may not yet have vaccines or treatments against COVID-19, but there is one powerful combo that can help stop the spread of the virus, which many of us already have access to: soap and water.

There’s a reason why governments and public health experts worldwide have been telling us to wash our hands – it really works. Good hand hygiene could reduce cases of respiratory diseases by 20%, and diarrhoea by 30%. That means it has potential to have a huge impact on the spread of the coronavirus.

Why does it work?

It comes down to chemistry. The virus itself if is made up of genetic material wrapped in a fatty coating. Soap molecules can disrupt this lipid membrane, causing it to fall apart. The virus’ “spike” proteins, which normally help it to invade human cells, are lost into the surrounding environment rendering the virus inactive. With the fragments of the virus enveloped by the soap molecules, these are then washed away when you rinse your hands.

The physical action of scrubbing your hands can also help to dislodge viral particles, which is why there has been so much emphasis on how we wash our hands and how long for. It does not matter how good your soap is if you do not apply it thoroughly enough.

Soap or sanitiser?

Sanitiser could seem like a more high-tech approach than a lowly bar of soap, and sanitisers with a very high ethanol content can act in a similar way to soap and interfere with the lipid membrane. However, they are generally not as effective as soap and water because the viral particles remain on the surface of the skin, rather than being rinsed away.

What about in communities without access to soap and water?

This is all well and good when we have soap and clean water at hand, but what about the 3 billion people worldwide who do not have it at home? Or the 1 in 6 health care facilities that lack hand hygiene facilities at points of care?

In the absence of other health interventions that can prevent the spread of viruses, such as vaccines, this is a major concern for governments and aid organisations working to contain the spread of COVID-19 in the world’s poorest countries. They are drawing up a variety of strategies, old and new, to overcome this problem.

Handwashing stations

One approach that proved successful in West Africa during the 2014–2016 Ebola epidemic has once again been deployed there in response to COVID-19. Simple handwashing stations are being installed in schools, bus stations, health care centres and other public places. These are made up of just two buckets, one containing a solution of chlorine and water, and a second to collect the wastewater. In some areas, dots are being painted on the ground for people to stand on, so that they maintain physical distancing while lining up to use the handwashing stations.

Innovative technology

PATH, an NGO that uses innovative technology to improve health, has partnered up with the outdoor equipment manufacturer MSR’s Global Health wing to produce a Community Chlorine Maker. Using just water, salt and a power source, such as a car battery, the device can produce enough chlorine to treat 200 litres of water in a matter of minutes.

This was developed before the pandemic to address this challenge more generally, but the device is now needed more than ever, and 13 countries across the world have put in requests to PATH for the devices. People all over the world are also coming up with their own solutions, such as the solar-powered hands-free handwashing station developed by students in Uganda.

Public awareness

As well as increasing access to soap and water, there is a need for public awareness campaigns to make sure people use them. Globally, only 1 in 5 people wash their hands after going to the toilet.

Governments and health organisations are working with community leaders, religious leaders and celebrities to promote the importance of regular and thorough handwashing. A video of policemen doing a “handwashing dance” in the Indian state of Kerala has gone viral, and a Nigerian musician, Cobhams Asuquo, has released a song called "We go win (corona)".

What about after the pandemic?

While all these efforts to promote handwashing are happening in the name of COVID-19, they will also have an impact on the spread of many other deadly diseases. When this pandemic is over, maintaining the progress made could save countless lives every year from diseases like cholera, typhoid and pneumonia.