© Provided by The Guardian Photograph: Dominic Lipinski/PA

The public should wear homemade masks when they venture outdoors to help reduce the spread of coronavirus, according to scientists who claim Britain’s masks policy does too little to prevent infections.

Prof Sian Griffiths, who led the Hong Kong government’s investigation into the 2003 Sars epidemic, said Britain should adopt the same approach as the US, where people are advised to make their own “cloth face coverings” and wear them in public spaces.



Trish Greenhalgh, a professor of primary care health sciences at Oxford University who recently completed a review on face masks, also advocated the use of masks in public and suggested an old T-shirt combined with kitchen paper would suffice.

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The US policy is being directed by the Centers for Disease Control and Prevention (CDC) and is designed to reduce at least some transmission of the virus while preventing a run on medical-grade masks needed by frontline health workers.



“The CDC advice in the US is pragmatic,” Griffiths said. “It recognises both the need to ensure the supply of masks for clinical situations where they are obviously needed at the same time as recognising that there could potentially be benefits in wearing ‘masks’ in public to prevent passing on the infection.”

The government’s scientific advisory group for emergencies (Sage) met on Tuesday to review the evidence on wearing face masks. The Guardian understands that the group is split on the best policy to adopt because the evidence is so weak.

Ministers are deeply reluctant to recommend the use of even homemade masks amid concerns that people will rush to buy medical masks and leave the NHS facing even greater supply shortages.

Public Health England recommends face masks for the NHS and in social care settings but does not advise healthy people to wear them outside. World Health Organization (WHO) guidelines state that while masks can help prevent people from passing on coronavirus, they are inadequate protection on their own from contracting it.

Greenhalgh, on the back of a review on face masks, said homemade versions could dramatically reduce the amount of droplets sprayed from people’s mouths, which can carry the virus if the person is infected.

“We should be covering our faces with homespun materials like cotton. Medical-grade masks are scratchy and uncomfortable. Your old T-shirt is soft and nice, and with a couple of layers of kitchen paper inside a double layer, it will reduce the droplets coming out of your mouth and nose by about 95%,” she said.

She added: “The public should not and must not divert medical-grade supplies.”



There is growing unease over the government’s reluctance to recommend the use of face masks. Doctors across the UK have now backed the Masks4AllUK movement, which argues that people should wear homemade masks when they go out.

At a press conference on Friday, the government’s chief scientific adviser, Sir Patrick Vallance, said that while Sage would look at the evidence, it was “absolutely crucial” that masks were available in hospitals and other high-risk transmission areas.

© 2020 Getty Images LONDON, ENGLAND - APRIL 21: A woman wearing a face mask walks past a piece of street art depicting an NHS worker on April 21, 2020 in the Shoreditch area of London, England. The British government has extended the lockdown restrictions first introduced on March 23 that are meant to slow the spread of COVID-19. (Photo by Andrew Redington/Getty Images) Chris Hopson, the chief executive of NHS Providers, which represents healthcare trusts across England, said the impact on the NHS must be fully assessed. “Fluid-repellent masks for health and care staff are key to safety and to avoid the spread of coronavirus,” he said.



“Securing the supply of masks, when there is huge global demand, is crucial. This must be a key consideration for government. There needs to be clear evidence that wearing masks, along with other measures, will deliver significant enough benefits to take us out of lockdown to potentially jeopardise NHS mask supply.”

Prof David Heymann, of the London School of Hygiene and Tropical Medicine, who chairs an independent advisory group to the WHO emergencies programme that is managing the Covid-19 pandemic, said the purpose of wearing face masks was to prevent the wearer from spreading the virus if they were infected themselves.

“Masks should not be worn by the general public to protect themselves as there is evidence that masks do not prevent infection by other respiratory infections such as flu,” he said.

“The best way that the general public can support government policy is to understand how to protect themselves and protect others if they are sick or believe they may be infected. This is by physical distancing, social distancing and frequent handwashing.”

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Stay at home to stop coronavirus spreading - here is what you can and can't do. If you think you have the virus, don't go to the GP or hospital, stay indoors and get advice online. Only call NHS 111 if you cannot cope with your symptoms at home; your condition gets worse; or your symptoms do not get better after seven days. In parts of Wales where 111 isn't available, call NHS Direct on 0845 46 47. In Scotland, anyone with symptoms is advised to self-isolate for seven days. In Northern Ireland, call your GP.