Government scientists are expected to recommend that the public should not wear medical face masks but could choose to wear a scarf or face covering during the coronavirus outbreak.
The scientific advisory group on emergencies, known as Sage, meets on Thursday to discuss the benefits of masks and is expected to tell ministers that the medical grade coverings should be prioritised for health workers only.
The World Health Organization has said there is little evidence masks act as a preventive measure to infection. However, some countries such as the US have made coverings mandatory for those going out in public. In Germany they must be worn on public transport.
Scientists are believed to be split on how effective coverings can be in blocking the transmission of the illness to other people.
England’s deputy chief medical officer, Dr Jenny Harries, said the fact the issue was being debated means “the evidence either isn’t clear or is weak”.
Asked on ITV’s Good Morning Britain whether face coverings could have an effect on the London underground, she said it was possible there could be “a very, very small potential beneficial effect in some enclosed environments”.
She continued: “But the evidence is really very, very difficult to tease out. It is not a simple yes or no, unfortunately.”
Countries insisting people use masks when they are out in public are usually coupling the instruction with very strict physical distancing, which makes it hard to tell which is making a difference.
The health secretary, Matt Hancock, has said it would be unlikely the government could provide free face masks to the public and the priority would remain giving medical masks to health staff.
The Northern Ireland secretary, Brandon Lewis, said the government would take a view on Sage’s advice on face masks but the core message continued to be that people should be physical distancing.
He said it was not right to compare the UK’s stance on face masks with other countries’ because each nation was at a different stages of the virus cycle.
Martin Marshall, chair of the Royal College of General Practitioners, told BBC Radio 4’s Today programme there was no research to support wearing a mask if you were fit and well, and there was even a risk of picking up the infection if people were constantly adjusting it and touching their face.
He said: “However, it’s common sense that if someone is coughing and spluttering then it makes complete sense to wear masks in order to protect other people and I think that’s what this is about.
World Health Organization (WHO) guidance on face masks has remained consistent during the coronavirus pandemic. It has stuck to the line that masks are for healthcare workers – not the public.
“Wearing a medical mask is one of the prevention measures that can limit the spread of certain respiratory viral diseases, including Covid-19. However, the use of a mask alone is insufficient to provide an adequate level of protection, and other measures should also be adopted,” the WHO has stated.
There is no robust scientific evidence – in the form of trials – that ordinary masks block the virus from infecting people who wear them. There is also concerns the public will not understand how to use a mask properly, and may get infected if they come into contact with the virus when they take it off and then touch their faces.
Also underlying the WHO’s concerns is the shortage of high-quality protective masks for frontline healthcare workers.
Nevertheless, masks do have a role when used by people who are already infected. It is accepted that they can block transmission to other people. Given that many people with Covid-19 do not show any symptoms for the first days after they are infected, masks clearly have a potential role to play if everyone wears them.
Sarah Boseley Health editor
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“I think the guidance we’re expecting to hear that people wearing a face mask is a voluntary activity, not mandated, makes sense and certainly makes a lot of sense to focus limited resources that we have at the moment on those who have greatest need and that’s the health professionals.”
He said people with common viruses and colds might want to wear a mask in public once restrictions had been lifted further down the line.
He said: “This sophisticated kit is likely to be more rigorous, more useful, but actually it’s perfectly reasonable to wear a bandanna around your mouth or whatever, that will work. It won’t be quite as good but it will be good enough given the evidence you’re not protecting yourself by wearing these masks unless you happen to be coughing and spluttering.”
