The evidence review, published on Monday, suggests cloth masks – whether bought or home-made – could filter viral particles during coughing at between 50 and 100 per cent of the efficiency of surgical masks. It also quotes estimates which suggest that between 40 and 80 per cent of infections occur from individuals without symptoms.
Some scientists have questioned whether those who wear masks are less likely to comply with social distancing measures. The theory follows suggestions that cyclists who wear helmets are likely to take more risks on the road.
But the review says: “While there is anecdotal evidence of individual risk compensation behaviour, at a population level the introduction of safety measures like HIV prevention measures, seatbelts and helmets have led to increased safety and even increased safety-oriented behaviour.
“There is no evidence for individual risk compensation amongst the public during epidemics.”
Venki Ramakrishnan, the chairman of the Royal Society’s data evaluation and learning for viral epidemics committee, which carried out the review, said: “The evidence shows that, if used widely and correctly, face masks, including home-made cloth masks, can help to reduce viral transmission in situations where social distancing is difficult to maintain consistently.
“Such situations include busy public transport, shopping and other potentially crowded public or workspaces. The British public has shown a great willingness to take action to reduce the spread of this terrible pandemic, and I am sure they would take this latest additional step.
“Our top priority should be to protect the NHS and care workers, so the public should absolutely not be rushing out to get surgical masks. However, the scientific evidence shows that even home-made masks can help to reduce the spread of the virus.”