Should you wear a cloth face mask to protect others?

It is no substitute for social distancing and washing your hands to stop the spread of Covid-19, but wearing a washable, cloth face mask when you go shopping or have to use public transport could help stop you spreading the virus if you don’t know you have it.

Man wearing a keffiyeh.
Cotton Keffiyeh. Anyone can do their bit to stop the spread of Covid-19 with a cloth face mask or fashion accessory.

Mayor of London Sadiq Khan has now called for the government to make the wearing of masks on public transport by the public compulsory despite the NHS and World Health Organisation not recommending their use.

In New York the wearing of cloth face masks in certain public places is now compulsory and the United States Centre For Disease Control recommends that cloth masks should be worn and can even be made at home from a cotton t-shirt.

In the UK an editorial in the British Medical Journal on 9 April advocated the use of cloth face masks in public “to retain contagious droplets, aerosols, and particles that can infect others and contaminate surfaces”. 

The BMJ says that while evidence of the effectiveness of wearing masks is lacking “some data suggest that cloth masks may be only marginally (15%) less effective than surgical masks in blocking emission of particles, and fivefold more effective than not wearing masks”.

A separate paper published in the BMJ states: “We believe that, worn both in the home (particularly by the person showing symptoms) and also outside the home in situations where meeting others is likely (for example, shopping, public transport), they could have a substantial impact on transmission with a relatively small impact on social and economic life.”

But you don’t need to go out and buy a cotton face mask or get to work cutting up an old t-shirt. You can wrap a cotton scarf, bandana, shemagh or keffiyeh around your nose and mouth. It could be your personal fashion and public health statement. Cold first wash, and then wash frequently.

The public should not, however, be wearing surgical or N95 masks as these must be reserved for health and other workers who need them. And you should still keep your distance from others and wash your hands often.