Scientists and politicians are continuing to discuss whether people in the UK should be wearing face masks to help slow the spread of coronavirus.

Eastern Daily Press: A shopper wearing a face mask amid the coronavirus pandemic. Picture: Chris BishopA shopper wearing a face mask amid the coronavirus pandemic. Picture: Chris Bishop (Image: Archant)

Some experts believe everyone should be wearing masks in public places, but hospital bosses have warned that wearing them would “potentially jeopardise NHS mask supply.”

So just how effective are face masks? And will I be depriving the NHS if I wear one? We take a look at the key questions.

• What is the UK advice on face masks?

It is currently not compulsory to wear a mask or face covering, but the government has said it is continuing to monitor the situation.

Public Health England (PHE) recommends masks for NHS staff and social care workers, but does not suggest other people wear them outside.

London Mayor Sadiq Khan has called for a change in advice to add “another layer of protection” to members of the public against COVID-19.

He has previously said: “In those circumstances where we can’t keep our social distance, we can’t keep two metres apart, think about when you’re using public transport and you really have to, or you’re in a shop and you can’t keep two metres apart.

Eastern Daily Press: A taxi driver in Dereham wears a face mask amid lockdown due to coronavirus. Picture: Denise BradleyA taxi driver in Dereham wears a face mask amid lockdown due to coronavirus. Picture: Denise Bradley (Image: Copyright: Archant 2020)

“Wearing a non-medical facial covering makes it less likely you may inadvertently give somebody else COVID-19.”

• Is the advice likely to change?

A top doctor has said it would make sense to advise the public to wear coverings on a voluntary basis and expects the government to alter its guidance.

The chairman of the Royal College of General Practitioners, Professor Martin Marshall, said: “If (people) are coughing and spluttering then it makes complete sense to wear masks in order to protect other people.”

He told the BBC’s Today programme: “I think the guidance that we’re expecting to hear is that the wearing of face masks is a voluntary activity, not mandated, and it 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.”

MORE: Coronavirus tests to be made available to prison staff, delivery drivers and other essential workers

Government scientific advisers finalised their advice on the wearing of face masks by the public on Thursday.

The prime minister’s official spokesman said the cabinet was told that the recommendations of the Scientific Advisory Group for Emergencies (Sage) had been submitted for ministers to consider.

• Are they effective?

Leading experts have cast doubt on the strength of the evidence on the benefits of face masks.

At Thursday’s Downing Street press conference, chief scientific adviser Sir Patrick Vallance said the evidence on face masks “has always been quite variable, quite weak and difficult to know”.

According to European scientists, there is no evidence that non-medical standard face masks or other covers offer protection to wearers.

The European Centre for Disease Prevention and Control says that a non-medical mask has a filter efficiency of between two and 38pc.

However, the World Health Organisation recommends face mask use for people who are taking care of a person with COVID-19, or if they are coughing or sneezing themselves.

Eastern Daily Press: A pedestrian wearing a face mask in Norwich amid the coronavirus pandemic. Picture: Denise BradleyA pedestrian wearing a face mask in Norwich amid the coronavirus pandemic. Picture: Denise Bradley (Image: Copyright: Archant 2020)

• Are there enough masks for key workers and the general public?

NHS bosses have urged the government to make sure there are enough masks for medical staff before making any compulsory orders for the public.

Chris Hopson, chief executive of NHS Providers, which represents hospitals and NHS trusts in England, asked ministers to “fully assess” the potential impact on healthcare supplies.

MORE: Who are essential workers and how can they get tested for coronavirus?

In a statement on Monday, he said: “Fluid repellent masks for health and care staff are key to safety and to avoid the spread of coronavirus.

“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.”

Eastern Daily Press: Face coverings should be worn in enclosed spaces such as public transport and some shops, the government has said. Photo: PA WireFace coverings should be worn in enclosed spaces such as public transport and some shops, the government has said. Photo: PA Wire (Image: PA Wire/PA Images)

• Will I be given a mask if they are made compulsory?

The government has said it “can’t promise” everybody will be given a mask for free if the public are forced to wear them.

Matt Hancock was asked the question by former Labour minister, Hilary Benn, in the House of Commons, and replied: “I can’t promise that we will give everybody free masks, I mean that would be an extraordinary undertaking, and we do have to make sure that we have supplies available especially for health and social care staff, where the scientific advice throughout has been that the wearing of masks is necessary in those circumstances and we’ve got to make sure the provision is there for them.”

• Can I make my own mask?

Masks can be made from cloth materials found at home, or items that can be wrapped around the face such as a scarf.

Trish Greenhalgh, professor of primary healthcare at the University of Oxford, told a Royal Society of Medicine web briefing: “How do you make your own mask? You take two pieces of cotton, or a piece of cotton folded over, and you take a pantyliner or something like that 1/8 with 3/8 waterproof backing, you stick it between those.

“And then you hook it around the back of your ears.”

• What types of mask exist?

The main types of mask can be divided into three types: homemade cloth masks, surgical masks and N95 respirators.

In the US, the Centres for Disease Control and Prevention (CDC) has recommended the use of cloth masks in environments where it may be hard to socially distance.

These can help prevent spreading the virus by coughing, sneezing or speaking.

MORE: How charities and frontline support groups can get PPE

Surgical masks do not create a seal on the face but are designed to prevent the spread of large droplets and protect medical staff from splashes.

N95 respirator masks can help prevent the spread of small particles, are tight-fitting to the face and can filter up to 95% of airborne particles, the CDC said.

While medical masks have clear evidence supporting their effectiveness, deputy chief medical officer Dr Jenny Harries urged the general public not to use them.

She said: “The number one thing is, we must leave our medical masks, if you like, for those people that need them at the frontline, because there is clear evidence that is beneficial.”

• Do homemade masks work for doctors?

European researchers have suggested cloth masks may not be effective for healthcare settings.

The European Centre for Disease Prevention and Control said rates of illness were much higher among healthcare staff using masks made out of cloth instead of surgical masks.

It said: “Altogether, common fabric cloth masks are not considered protective against respiratory viruses and their use should not be encouraged.

“In the context of severe personal protective equipment (PPE) shortages, and only if surgical masks or respirators are not available, homemade cloth masks (eg scarves) are proposed as a last-resort interim solution by the US CDC until availability of standard PPE is restored.”

- For the latest COVID-19 news, visit the Norfolk Coronavirus Updates Facebook page.

- You can also subscribe to our daily coronavirus newsletter, providing all the latest from where you live.