Most scientific studies conducted to date suggest face masks do reduce the spread of coronavirus in enclosed indoor settings.
A number of studies have concluded that face coverings reduce the spread of airborne droplets that carry covid bacteria between people.
The latest data, from the Lancet, studies in China and Thailand as well as on the USS Theodore Roosevelt, suggests a mask stops up to 80 per cent of droplets from being released into the air by a person wearing a mask, and they also block around 50 per cent of them being inhaled by a potential victim.
Covid-19 is spread through these airborne droplets when people cough, sneeze or talk – and standing in close proximity can assist transmission.
The US Centers for Disease Control found in one real-world data experiment the coverings were useful. Two hair stylists who had Covid symptoms worked on 139 customers in eight days.
Everyone involved wore masks and no one out of the 67 who volunteered to be tested came back positive. Another experiment in China looked at 124 houses where there had been a case of the virus.
It found transmission was reduced by 79 per cent by wearing a face covering. And an example also came from the USS Theodore Roosevelt – a cramped vessel with tight living quarters and makes social distancing hard.
But the study found when using face coverings there was a 70 per cent reduced risk of infection. Meanwhile in Thailand a retrospective case-control study discovered out of 1,000 spoken to during a contact tracing probe, those who said they wore a covering had a 70 per cent reduced chance of catching Covid.
And the Lancet in its report looked at 172 studies from 16 countries and concluded wearing a mask gives a person just a three per cent chance of getting the virus. Edinburgh University looked into the different types of masks people can wear and found homemade ones can be effective.
Researchers tested seven types, including surgical masks, respirators, lightweight and heavy-duty face shields and handmade masks. All of them – except ones with a valve – reduced the distance droplets could get by at least 90 per cent.
The CDC says: ‘Experimental and epidemiological data support community masking to reduce the spread of SARS-CoV-2. The prevention benefit of masking is derived from the combination of source control and wearer protection for the mask wearer.
‘The relationship between source control and wearer protection is likely complementary and possibly synergistic, so that individual benefit increases with increasing community mask use,’ the agency added.
The WHO says: ‘Masks should be used as part of a comprehensive strategy of measures to suppress transmission and save lives; the use of a mask alone is not sufficient to provide an adequate level of protection against Covid.
‘If Covid is spreading in your community, stay safe by taking some simple precautions, such as physical distancing, wearing a mask, keeping rooms well ventilated, avoiding crowds, cleaning your hands, and coughing into a bent elbow or tissue. Check local advice where you live and work. Do it all!’