Which masks can REALLY keep you safe against the rapid spread of coronavirus?

The defining image of the coronavirus outbreak has been pictures of people with their faces covered by masks.

And it’s not just in Wuhan, where the Chinese government has made it compulsory for residents to cover their noses and mouths in public.

The rapid spread of the virus has prompted some in the UK to wear them, too, and as a result demand is beginning to outstrip supply.

The shortage is compounded by the fact that China is the world’s biggest manufacturer of sanitary masks, producing half the supply — but its government is commandeering these.

As a result, respirator masks — used to keep out airborne particles such as dust and fumes — are now leaping to the top of Amazon’s bestseller lists.

But Public Health England says there is little evidence that masks worn outside the clinical setting will protect the public.

Dr Manal Mohammed, a lecturer in medical microbiology at the University of Westminster, says that viruses are mainly spread by droplets expelled from infected people, which can travel up to 6ft — so surgical-style masks would have limited benefit.

‘The problem is, the mask isn’t intended to protect the surgeon,’ she says. ‘It’s intended to stop droplets from the surgeon’s mouth or nose getting into the patient’s wound and causing infection.’

However, tighter-fitting, thicker respirator masks can offer better protection. Known as filtering face pieces (FFP), they are divided into three protection levels.

The lowest is an FFP1, like those used by cyclists to protect them from pollution. At the highest level, FFP3 masks keep out 99 per cent of pollutants — including particles containing the flu virus and coronavirus.

These masks are made of denser materials that may carry a charge that traps the virus, so it dies. As these can be more difficult to breathe through, they tend to be fitted with outlet valves.

So, if the coronavirus gets a foothold in Britain, would masks help?

We asked Dr Mohammed and personal protection industry expert Nick Moore to review a selection He liaises with the NHS on masks for virus outbreaks, and helped design ones to protect against SARS, avian flu and swine flu.

He calculated the usefulness of these masks in terms of how well they would protect the wearer and stop them from spreading disease to others.

Three-ply surgical mask 

Pack of ten, £12, ebay.co.uk

What is it? Surgical masks are all made from three-ply material that works like blotting paper to soak up droplets coming from the nose or mouth.

Most of the masks available to the public are already sold out, which is why these come with a big mark-up.

Expert verdict: ‘These masks will provide some protection, as they will block liquid droplets and limit their travel,’ says Dr Mohammed.

‘However, they do not block smaller particles that can pass through the material.

‘They also leave the eyes exposed, and there is evidence that some respiratory viruses — such as flu — can infect people through their eyes.’

They must also be changed often, she says, as they draw in moisture and debris, so effectively become useless.

‘In the Far East, these types of masks are used as a courtesy to stop you spreading your cold, but they won’t do much to protect you from catching other people’s germs,’ adds Nick Moore. ‘If you’re trying to avoid coronavirus you might as well save your cash.’

Safety rating for you: 1/5

For others: 2/5

Cup-shaped valved paper mask

FFP2 valved moulded anti-virus flu mask, pack of 20, £74.99, amazon.co.uk

What is it? Advertised as being ‘anti-virus and flu’, this mask is made from a thick filter paper, and is designed to be thrown away after a day.

Expert Verdict: ‘This does not form a tight enough seal around the nose and mouth to keep out the virus,’ says Nick Moore.

‘It is worth noting that no mask would offer sufficient protection on a man with a beard, as the hair would stop the mask forming a tight enough seal.

‘If you had coronavirus, this mask wouldn’t protect other people either, because it has a valve for breathing out moisture, to make it less hot and sweaty to wear.

‘This valve does not filter out viruses, so the virus would come out with the moisture in your breath.’

Safety rating for you: 2/5

For others: 1/5

Rubbery filter respirator mask 

GVS filter technology SPR501 Elipse P3 dust half-mask respirator, £21.25, amazon.co.uk

What is it? This is made out of a soft rubbery material, and has filters on either side of the nose to screen out any incoming particles, including viruses. It also has an outlet valve in the middle to make it easier to breathe.

Expert verdict: ‘This mask has a rating of FFP3, the highest level of protection,’ says Nick Moore. ‘

‘If I were a medic treating a patient in China, I would be happy wearing this one, along with other protective measures, such as goggles to protect my eyes.

‘It might be uncomfortable to wear all day. But it would do the job as long as it fitted you. In terms of protecting others, it has quite a large exhalation valve, so the virus could be expelled with your breath.’

Safety rating for you: 4/5

For others: 2/5

Gas mask with built-in goggles

Saim respirator gas safety mask, £15.99, amazon.co.uk

What is it? Complete with built-in goggles and gas filters, it looks like it should protect you from nuclear warfare.

Expert verdict: Although this is billed as good enough for ‘military’ use, Nick Moore says it is completely the wrong kind of mask for a virus outbreak, because it does not have the right filter.

‘The mask is so solid that moisture from your breath wouldn’t be absorbed,’ he says.

‘So if you were breathing out the virus, it would sit on the inside of the mask waiting to be expelled. It’s useless for both you and others.’

Safety rating for you: 0/5

For others: 0/5

Netted mesh moulded mask 

AlphaFlow moulded AMF-3V FFP3 respirator mask, pack of ten, £59.05, arco.co.uk

What is it? Unlike the other models, this respirator mask comes with a netted mesh on the outside.

This means the inner layer can be made of thinner, flexible material that makes it easier to breathe through.

Expert verdict: ‘When I conducted a fit test, to check how many particles were getting in, it passed comfortably, so it would offer good protection against a virus,’ says Nick Moore.

‘However, even though it’s a good fit and the highest level of protection, this one has a valve —so the virus would come out with the moisture in your breath and could infect others.’

Safety rating for you: 4/5

For others: 2/5

Lightweight foldaway mask 

Alpha Solway C3V C Series fold flat FFP3 respirator, pack of 20, £90.70, arco.co.uk

What is it? This lightweight fabric mask looks like a surgeon’s. It has the highest protection rating.

Expert verdict: ‘It’s a fold-flat mask which is easy to carry around. It offers a high level of protection with minimum fuss,’ says Nick Moore. ‘This would contain sneezes well, but the virus could come out through the valve.’

Safety rating for you: 3/5

For others: 2/5

Rigid dust and mist mask

3M cup-shaped particulate respirator, pack of three, £9.49, robertdyas.co.uk

What is it? A basic rigid cup, with a wire nose band.

Expert verdict: ‘This offers only FFP1 protection to filter non-toxic particles,’ says Nick Moore. ‘It offers more protection than a surgical mask, but is not designed for anything toxic, and certainly not a virus.

‘This has no valve, so would help contain coughs and sneezes and stop them spreading so far. It would help keep the virus within the mask, but it wouldn’t be contained completely.’

Safety rating for you: 1/5

For others: 2/5