Q&A: Does handwashing stem the transmission of Covid-19?

Is handwashing still an important way to reduce the spread of Covid-19?

In the early days of the pandemic, public health experts emphasised handwashing as a way to prevent infection and the government launched a “Hands, Face, Space” campaign to encourage people to wash their hands, wear masks and keep 2 metres apart. Subsequent research has shown the biggest risk of Covid-19 transmission is through particles in the air.

Why did we focus on handwashing?

When little was known about Covid-19, researchers focused on fomites – surfaces such as handrails where the virus might be able to survive without a host for some time – because other diseases such as norovirus can be transmitted that way.

How does Covid-19 spread?

Surface transmission may happen, but speaking and coughing seem to play a much larger role, because we emit tiny aerosol water particles containing the virus. Indoors, those particles can linger for minutes or hours, leading the US Centers for Disease Control and Prevention to suggest last week that people wear two masks. It now says surface transmission is “not thought to be a common way that Covid-19 spreads”.

Can handwashing prevent the spread of Covid-19?

Although there is limited evidence that fomites do play a role, there is no evidence that Covid does not linger on surfaces. Public Health England put handwashing and surface cleaning at the top of updated guidance published earlier this month. The risk of contracting the virus through touch may be lower, but it may still exist.

Are there any risks from washing hands too much?

In addition to the substantial cost and effort involved in spraying and wiping surfaces in schools, public transport and elsewhere, concerns have been raised by some researchers that bacteria and viruses may become resistant to disinfectants. Scientists at the University of the Free State found some rare bacteria were resistant to commercially available disinfectants in South Africa.

Is handwashing preventing other diseases?

Although handwashing may have a limited role in preventing the transmission of Covid, there is substantial research that it reduces the spread of colds, influenza, norovirus and gastro-intestinal infections.