Coronavirus: Face masks ‘reduce deadly power of virus’: US research

Masks can reduce the amount of virus that gets into someone’s system, protecting the wearer and others, according to new research.

There is growing evidence that masks reduce the amount of virus that gets into someone’s system. Picture: Paul Jeffers

Masks do help to protect the wearer, as well as people they meet, according to research by infectious disease experts.

A report from a team at the University of California, San Francisco, says that masks can reduce the amount of virus that gets into someone’s system, meaning they do not get as badly sick.

In England, face coverings are mandatory on public transport and will become so in shops and supermarkets from July 24. The requirement appears to have strong public support, with only 19 per cent of Britons opposing compulsory wearing of masks in shops, according to a survey last week by the research company ORB International.

The paper is due to be published in the Journal of Internal Medicine but was made available in advance by the researchers. Monica Gandhi, one of the study’s co-authors, who is associate division chief of the infectious diseases program at San Francisco General Hospital, said: “You will get in a lower dose of virus if you wear a mask and are exposed to COVID-19 and are very likely to have mild or no symptoms.”

She told The Times that her research suggested the government should go further in its recommendations for the wearing of face coverings. “The research suggests that we should go towards universal population-level masking to control infections and to limit the severity of disease.”

That would include wearing masks in workplaces where employees did not each have a private office, she said. Matt Hancock, the health secretary, has said masks do not have a role to play in infection control in offices.

Under the “theory of viral inoculum”, a lower initial dose of Sars-Cov-2 gives the immune system a better chance of fighting the disease. The new paper draws evidence suggesting that masks reduce the amount of viral droplets that get through to the wearer’s airways.

One study, in hamsters, showed that animals exposed to the virus through a surgical mask partition had milder cases of COVID-19. Outbreaks on cruise ships where passengers wore masks typically resulted in higher rates of asymptomatic, or milder infection, the report says.

The authors concluded: “Exposing society to SARS-Cov-2 without the consequences of severe illness with public masking could lead to greater community-level immunity and slower spread as we await a vaccine.”

Some scientists continue to argue that masks give people a false sense of security. They point to a lack of high-quality trials investigating their use.

None of the evidence in the new paper comes from controlled trials in humans, because of ethical concerns about deliberately exposing volunteers to different doses of the virus.

Many proponents of masks say the government should make them compulsory in all indoor settings. The Church of England is expected to advise its congregations to wear masks in the pews. As well as outlining the requirement for masks on transport and, from July 24, in shops, official guidance now also states: “People are also encouraged to wear face coverings in enclosed public spaces where there are people they do not normally meet, such as a place of worship.”

Adam Zeineddine, right, owner of My Oh My cafe and barista Andy Balloch adopted the use of masks early. Picture: Paul Jeffers

A church spokesman said on Monday that its own guidance was “being updated in light of this”. The church did go further than following government advice when it banned priests from places of worship – a move that was criticised by members of the General Synod last week – but it is not expected to make masks mandatory for worshippers.

The church has already advised that the risk of transmission during the administering of communion is “relatively low especially if face coverings are worn” and says in its latest guidance that churches should be “using protective screens and face coverings” but adds that this is voluntary.

The Muslim Council of Britain has advised mosques to consider providing “face masks for worshippers without their own” while the United Synagogue has made them mandatory for Jewish worshippers.

The Times