Healthy Britons have been repeatedly told during the coronavirus crisis 'there is no evidence' wearing face masks will protect them from infection.

But data from countries which enforced mandatory mask-wearing suggests they have helped curb the spread of the virus and keep death rates low.

Austria seemingly managed to reverse its crisis by making masks compulsory on April 6, following a spike in infections in late March.

In the fortnight since the rule was introduced, the nation's daily rise in positive cases dropped from 90 per million people every day to less than 10.

The Czech Republic and Slovakia were the first two countries in Europe to issue decrees making masks compulsory - and both have tiny infection rates per capita.

Just 63 Czechs per 100,000 has been infected and less than two per 100,000 have died from the virus.

In Slovakia, 21 per 100,000 people have caught it and just 0.2 per 100,000 have succumbed to the illness.

By comparison, 182 out of every 100,000 Britons has been infected and 25 per 100,000 have fallen victim to the virus.

Similar patterns can be seen for mask-wearing countries outside of Europe, with South Korea and Japan halting major outbreaks without imposing lockdowns.

It comes as a 100-strong group of top doctors today called for ministers to change its guidance on face masks.

The group wants to encourage Britons to make 'reusable cotton masks from simple items you can find in your house' and leave surgical masks for healthcare workers.

How the UK compares to other mask wearing countries: Austria made it mandatory to wear one to supermarkets or shops on April 6, following a spike in infections in late March. In the fortnight since the rule was introduced, the nation's daily increase in cases has plummeted by 90 per cent

The UK's death rate is four times as high as second-place Austria's. More infections directly leads to more deaths

Two people are pictured wearing masks on London's Clapham Common on Sunday. Ministers could make a decision this week on whether to order the use of protective equipment for millions of Britons in the workplace and on public transport

Fewer than eight out of every 100,000 Japanese people have contracted the virus and 0.1 per 100,000 have been killed by it. In South Korea, that number is 20 and 0.5, respectively.

China, which also mass-issued millions of masks to its people, did suffer a major outbreak - more than 80,000 people caught the virus.

But because of its vast population of 1.4billion, its per capita infection and death rates are skewed. Just six out of every 100,000 Chinese people became infected and 0.3 per 100,000 died.

THE TRUTH ABOUT FACE MASKS: WHAT STUDIES HAVE SHOWN Research on how well various types of masks and face coverings varies but, recently, and in light of the pandemic of COVID-19, experts are increasingly leaning toward the notion that something is better than nothing. A review of scientific literature by the University of East Anglia found the masks have a 'small protective effect' that could shield elderly and vulnerable people from contracting the virus in crowded places. The researchers advise they people wear one on public transport, at the supermarket or in hospitals. But they say the evidence is not strong enough to recommend widespread use of masks in the general population. A University of Oxford study published on March 30 concluded that surgical masks are just as effective at preventing respiratory infections as N95 masks for doctors, nurses and other health care workers. It's too early for their to be reliable data on how well they prevent infection with COVID-19, but the study found the thinner, cheaper masks do work in flu outbreaks. The difference between surgical or face masks and N95 masks lies in the size of particles that can - and more importantly, can't - get though the materials. N95 respirators are made of thick, tightly woven and molded material that fits tightly over the face and can stop 95 percent of all airborne particles, while surgical masks are thinner, fit more loosely, and more porous. This makes surgical masks much more comfortable to breathe and work in, but less effective at stopping small particles from entering your mouth and nose. Droplets of saliva and mucous from coughs and sneezes are very small, and viral particles themselves are particularly tiny - in fact, they're about 20-times smaller than bacteria. For this reason, a JAMA study published this month still contended that people without symptoms should not wear surgical masks, because there is not proof the gear will protect them from infection - although they may keep people who are coughing and sneezing from infecting others. But the Oxford analysis of past studies- which has not yet been peer reviewed - found that surgical masks were worth wearing and didn't provide statistically less protection than N95 for health care workers around flu patients. However, any face mask is only as good as other health and hygiene practices. Experts universally agree that there's simply no replacement for thorough, frequent hand-washing for preventing disease transmission. Some think the masks may also help to 'train' people not to touch their faces, while others argue that the unfamiliar garment will just make people do it more, actually raising infection risks. If the CDC does instruct Americans to wear masks, it could create a second issue: Hospitals already face shortages of masks and other PPE. Advertisement

It comes after more than 100 top UK doctors backed calls for the public to wear homemade face masks to protect themselves and others from contracting the virus.

They signed a letter saying they were 'increasingly alarmed at official inaction over the need for the public to wear face masks'.

Ministers could make a decision this week on whether to order the use of protective equipment for millions of Britons in the workplace and on public transport.

The doctors spoke out ahead of a meeting of the Government's scientific advisers tomorrow to review evidence on whether masks should be made compulsory.

Britain is out of step in its guidance, with other European countries including Germany, Italy and Spain now recommending their use.

The doctors are backing the Masks4All campaign which is calling for 'ordinary homemade masks' to be worn by the public to help stop those with the disease spreading it to others.

Signatories of the letter include John Ashton, a former president of the Faculty of Public Health, and Martin McKee, a professor of European public health at the London School of Hygiene and Tropical Medicine.

Their missive to The Times said: 'Official UK policy is illogical… The latest guidance on PPE [personal protective equipment] says that people should wear masks in hospital waiting rooms 'to reduce both direct transmission and environmental contamination'. Why not elsewhere?

'The thousands of coronavirus mutual aid groups could make enough homemade masks for everyone, so it would cost next to nothing. Instructions are easily available, for example, at masks4all.org.uk.'

A petition has also been started by Masks4All urging the Government to make masks mandatory in the UK.

The group advises making 'reusable cotton masks from simple items you can find in your house', such as scarves or towels.

The campaigners stress that surgical masks and respirators should be reserved for health professionals.

Authorities across Europe, including in Germany, France and Spain, have put their faith in masks as part of their postlockdown plans.

The coverings are already common in China, Japan and South Korea. Sir Patrick Vallance, chief scientific adviser, has warned that the decision is complicated by a lack of evidence that wearing a mask can prevent users from contracting coronavirus.

However, they can prevent any infected wearer from spreading the virus further through coughs and sneezes.

London Mayor Sadiq Khan has urged the Government to change its advice on masks to combat the spread of the virus.

He was supported by former Health Secretary Jeremy Hunt, who said such a move would be 'sensible' given how social distancing can be impossible on trains and buses.

Labour leader Sir Keir Starmer said it was 'inevitable' the Government would have to change its advice, which at present states that masks are only needed in hospitals.

It comes after US health regulators last week warned parents not to put face masks on babies during the coronavirus pandemic as it may suffocate them.

While the wider public have been advised to wear a mask or face covering when they go out in order to prevent the infection spreading, pediatricians say it may be harmful for babies.

The Centers for Disease Control (CDC) said infants have such small airways that a mask could do more harm than good and doctors have warned of suffocation.

How to make your own coronavirus face mask: Online DIY tutorials detail method for vacuum cleaner bag or T-shirt to create protection that leading scientists say is effective against bug

A man is seen using a nappy as a makeshift face mask in Brooklyn, New York City

IF YOU CAN'T GET A MASK, SHOULD YOU MAKE ONE? Experts in the US have suggested home-made masks could be a powerful defence against the coronavirus if there is a shortage of masks. A 2013 study by Cambridge University found that next to a surgical mask, a vacuum cleaner bag provided the best material for a homemade mask. After a vacuum bag, kitchen towels were fairly protective, but uncomfortable. Masks made of T-shirts were very tolerable, but only worked a third as well as surgical mask. The researchers concluded that homemade masks should only be used 'as a last resort.' Public Health England still does not recommend Britons wear face masks, unless they are infected themselves. The health body also does not advise people use items of clothing as makeshifts masks, because they it claims they offer practically no protection. Advertisement

The World Health Organization (WHO) maintains that surgical masks do not stop people from catching coronavirus.

The United Nations’ health body was forced to review new evidence from Hong Kong claiming mass-issuing masks may have helped contain the pandemic.

But the WHO maintains the public should not wear them outside because there is still no proof they prevent infection.

In updated guidance published earlier this month, the health body said masks were only useful for healthcare workers and patients who test positive.

The WHO acknowledged the virus can be transmitted by people who do not have symptoms, but said it must still spread via droplets which can pass through the masks' big filters, or on contaminated surfaces.

According to its new advice, people with symptoms should wear a face mask, self-isolate and call for an ambulance.

Only those caring for someone in close proximity should wear a mask, the WHO says.

Although scientists say the vast majority of masks do not have fine enough filters to stop viruses getting through, there is a growing school of thought that they could be useful.

Even if they don't stop viruses in their tracks they could redirect air flow which might be carrying them into people's mouths or noses.

A smaller initial dose of the virus has been linked to less severe symptoms in some coronavirus patients.

Professor Ian Jones, a virologist from the University of Reading, said the mass-issuing of masks 'should now be considered' in the UK.

Warning that the crisis is spiralling rapidly, he told MailOnline: 'Anything that reduces the rate of transmission will bring it under control sooner.'

Professor Jones told MailOnline: 'For me it's very simple, the epidemic is currently running [rampant] and anything that reduces the rate of transmission will bring it under control sooner.

'On the basis that correct mask use would do no harm and potentially some good it should be considered.'

The good face-mask guide: As UK health officials consider urging everyone to cover their mouths MailOnline reveals the best from top surgical-level respirators costing £20 each or ten mouth covers for £1 each

Face masks could soon be an everyday sight in Britain as health officials admit that they are reconsidering their advice for people not to wear them.

In countries such as China, Japan and South Korea, wearing face masks when you're ill is common - East Asia has learned from deadly virus outbreaks in the past.

The West, however, is new to the idea and the coronavirus pandemic has triggered widespread use of face coverings in the US, France and Spain.

Britain's chief scientific adviser, Sir Patrick Vallance, said on Monday that there is an 'ongoing review' of official advice on masks.

For weeks the Government has told people not to bother with them and to make sure there are enough available for staff in hospitals and care homes who really need them.

Following a World Health Organization softening on the stance, however, they could soon be recommended to prevent the spread of COVID-19.

Although it is acknowledged that they don't do much to stop someone catching the virus, there is evidence they can stop already-infected people spreading it.

As officials consider changing guidance on face masks in Britain, here is what you need to know about the types available and their relative effectiveness:

Two types of mask meet high-grade medical standards - FFP3 and FFP2/N95. So what's the difference?

A man wearing a respirator face mask walks along Weston-super-Mare on Easter Sunday

The two main types of medical-grade face mask on sale in Britain are the FFP3 and FFP2, also known as N95, masks.

These are the types that doctors and nurses must use when treating patients with the coronavirus, and offer the most protection against viruses in the air.

They are particularly vital during 'aerosolising' procedures such as putting in a ventilator, which is when medical workers are most at risk of breathing in viruses.

FFP stands for Filtering Face Piece, with FFP3 giving the highest level of protection against virus and bacterial infections, while FFP2 is the level below.

NHS guidance is for medics to use the FFP3 masks, while FFP2 is recommended by the World Health Organization and is the equivalent to the US's N95 mask.

The N in N95 stands for Not resistant to oil - because the mask is a particle respirator only and doesn't protect against fluids - while the 95 means it filters out 95 per cent of airborne particles.

Health officials say that when FFP3s are not available, FFP2s can be used. The WHO recommends FFP2 and N95 respirators, which are widely used in other countries.

The N95 does not have the CE mark to show compliance with European safety standards, but has been tested against standards similar to these requirements.

How to make your own coronavirus face mask: Online DIY tutorials detail method for vacuum cleaner bag or T-shirt to create protection that leading scientists say is effective against bug

The worldwide coronavirus pandemic has led to a shortage of protective face masks, leading to a deluge of online tutorials ion how to make your own using a t-shirt or pillowcase.

Homemade masks offer significantly less protection than the N95 medical masks, which are made of a thick, tightly woven material that fits over the face and can stop 95 per cent of all airborne particles.

Public Health England still does not recommend Britons wear face masks, unless in a medical setting.

But there are good reasons to think DIY masks could be effective in tackling the pandemic, as they have been widely used in Hong Kong,Mongolia and South Korea -countries that largely have the disease under control.

MailOnline has investigated how you can make your own face mask using everyday household items such as a t-shirt, kitchen towel or vacuum bags.

How to make a face mask from a t-shirt

A YouTube tutorial by Runa Ray shows how to make a face mask without any need for sewing, using just a plain t-shirt.

First of all you need scissors, pencil and a ruler, and a t-shirt you don't mind being used to make a face mask.

Cut out a 16' by 4' rectangle from the middle of the t-shirt, then fold it in half, and measure four inches on either side.

Then mark the t-shirt with an even number of tassels on each side and use scissors to cut them.

Turn the t-shirt inside out and separate the corner tassels, but tie the remaining ones in-between.

Then with the remaining t-shirt material cut some ear straps using the hem of the shirt.

Attach the straps to the remaining outer tassels and you have yourself a face mask, with no sewing involved, and using an old t-shirt.

A slightly more complicated method has been perfected by researchers from the University of Pittsburgh also managed to design a face mask that could be used if 'commercial masks' are not available during a virus outbreak.

A woman wearing a mask walks past a closed shop window display during the pandemic lockdown in Manchester

They used a regular cotton t-shirt, which was boiled for 10 minutes and then air-dried to sterilise the material, but also to shrink it.

The researchers used a marker and ruler to measure out what they wanted to cut and then formed the mask using an outer layer and then eight inner layers covering the nose and mouth.

The mask does not require any sewing, and instead involves it being tied multiple time around the face.

How to make a face mask from vacuum cleaner bags

By following the simple steps in the graphic, you can create your own face mask from a T-Shirt or vacuum cleaner bag,

Even UK politicians have got in on the act, with Gillian Martin, who is MSP for Aberdeenshire East, describing how she made a face mask from vacuum cleaner bags and elastic.

She told the Daily Record: 'I live in a small village and have been here for over 20 years. I don't want to worry or offend people when I go out.

'I started researching what other countries have been doing and came across a chart with the best materials to use to make a mask out of just about anything.'

'Just below medical material was a hoover bag. I have loads of them lying around and found Hepa-Flow bag that just goes on your Henry hoover'.

The chart the MSP is referring to from a University of Cambridge study which shows the materials that work the best against virus sized particles.

The top three are a surgical mask, vacuum cleaner bag and tea towel.

She added: 'I cut it up the bag and secured it with elastic. I live with my family of three who have all been self-isolating so I made one for each of us'.

Gillian Martin posted about her mask that she made from a vacuum cleaning bag

'I made it because I'm nervous of people coming up to me when I'm out walking the dog. I don't want to have to run away from them.'

Another popular YouTube method shows how to fold up a scarf, using hair ties at either end, to make a simple and easy no-sew mask. The same method can be used with a handkerchief and doesn't involve any sewing.

How to make a face mask from kitchen towel

For this you need two layers of kitchen towel and one of tissue.

You cut it in half, and then use masking tape on each end to ensure the mask is stiff.

Then you punch holes through either end of the mask and thread elastic bands through the holes.

Some Japanese women have even been posting instructions about how to make a face mask from a braThe method is simple and involves cutting off one cup with scissors and then sewing the bra straps on, so they can be attached to your face.

What types of masks can you buy online and how much do they cost?

This pack of two FFP3 masks is the best selling product for the type of respirator on Amazon

High-grade dust masks now used on NHS frontline: FFP3 face masks cost £40 for two

FFP3 masks are the gold standard for preventing the spread of airborne illnesses in hospitals.

They must fit tightly to the face and have all air drawn through a filter that is embedded in the fabric and catches almost every kind of particle as the air flows through.

They are primarily used as dust masks in the construction industry.

The masks are not widely available to members of the public online.

The top listing on Amazon - made by Wrexham-based company Toolpak - has sold out both on the marketplace and the firm's own website.

Toolpak's masks appear to be being sold by a third party for £39.99 for a pack of two on Amazon.

The N95 face mask being sold for £6.99 online is the US equivalent of the FFP2 mask in Europe

3M N95 masks are being sold for £25.99 for a six-pack on Amazon

Silver standard masks used by medical workers in US and UK: N95/FFP2 face mask cost £6.99 each

The N95 face mask is the US equivalent of the FFP2 mask in Europe and is backed by the World Health Organisation as suitable for medical use.

Its filter is not as strong as the FFP3 - it weeds out 95 per cent of particles, as the name suggests - but it is still highly rated for NHS staff.

UK health officials say FFP2 masks are second best to FFP3, and should be used if possible because they have a European seal of approval, but N95, which doesn't have CE approval, can be used if no FFP2 masks are available.

Masks of this grade are more readily available online from sellers in China.

The Amazon bestseller is a N95 mask sold by HJHY, a company based in China. They cost £6.99 but may not be delivered for a month or more. 43 per cent of people who bought the mask rated it just one star out of five.

Another product in Amazon's bestseller category is a £25.99 six-pack of N95 masks made by 3M and sold by Hpparty, another company based in China. Delivery dates start in mid-May and there are no customer reviews.

These disposable face mask covers offer some protection to users against respiratory diseases

Disposable surgical masks still used in most NHS hospitals: Ten for £9.39

The best known type of medical face mask, known as a surgical mask, is still being widely used by the NHS.

Doctors, nurses and healthcare workers are now instructed to wear these types of mask as a minimum at all times when working near confirmed or suspected coronavirus patients.

They are considered effective enough for most staff outside of intensive care or who are not inserting or removing breathing equipment.

Although they don't have built-in air filters, the masks can stop droplets of liquid, which are how the majority of the COVID-19 viruses are spread.

The best-selling product of this type under 'masks and respirators' on Amazon today is a ten-piece set of disposable face covers which costs £9.39.

The mask - with an average review rating of 3.5 stars - has an inner layer of cotton fabric, a middle layer of medical filter paper and an outer layer of waterproof fabric. It is sold by a company in London and delivers in early May.

Another top seller is a pack of 20 costing £7.97 and shipping from a company called T-Shell in Guangdong, China.

These types of masks are typically not reusable and should only be used for one day at a time.

Cycling masks can also provide people with a layer of protection from airborne particles

This mask is for sale for £11.99 on Amazon

Cycling masks designed to filter out pollution but with potential to stop viruses: £7.57 for six

While cycling masks remain untested regarding coronavirus, they are intended to provide a layer of protection from airborne particles.

They are designed to stop cyclists breathing in pollution when they ride through areas with heavy traffic.

They contain an air filter for this purpose, but are not regulated to the same standard as medical face masks so provide varying levels of protection.

High quality cycling masks, such as those made by the well-known UK brand Cambridge Mask Co. cost upwards of £20 and are reusable. The company has now sold out of all stock but is taking pre-orders.

Other cycling masks are available on Amazon, with the site's bestseller a £7.57 pack of six from a company called Diyii in China. The firm says the masks are good for those with sensitive skin allergies and can be washed repeatedly, and are also suitable for camping, running, travel and climbing.

Another top seller on the marketplace is a reusable mask sold by the Chinese firm KZKR-EU which costs £11.99 per mask and claims it will deliver within two weeks.

This valved gas mask is claimed to match up to the highest filtration standard

This rubber-sealed, military-looking mask is for sale for £29.87 on Amazon

The dramatic option: Respirator gas mask costing £34.86 for one

Perhaps the most dramatic-looking option of all masks is the gas mask respirator.

These are generally used by people spraying paint or other chemicals which it would be dangerous to inhale, or working in hazardous environments.

The masks have built-in valves fitted with filters which may be able to keep out droplets carrying the coronavirus.

The top listing on Amazon is a mask costing £34.86 and sold by SafeYear, a company based in Shanghai, China. The mask is rated FFP3, meaning it would be suitable for even the riskiest medical procedures.

Another top listed option on the site is a full-face rubber-sealed black mask which costs £29.87.

It is sold by the company Maikoler, based in China, and says it would be delivered by the end of May. The military-looking contraption has no customer ratings.

A woman in New York is pictured wearing a makeshift cloth facemask

A man in Fife, Scotland, shocked shoppers when he turned up at Asda wearing a mask made from a sanitary towel

T-shirts, bandanas and even sanitary towels: Homemade face masks may offer protection, too

Many people are opting to make masks at home using cloth or other materials - some have even been pictured using sanitary towels.

The Centers for Disease Control and Prevention (CDC) in the US recommends people use cloth face coverings when they go out in public and even has a how-to guide for people to make their own out of t-shirts or bandanas.

The intention of these is not specifically to protect people from catching the virus but to prevent the spread of it by encouraging such widespread use that people who are infected but don't know about it wear something that blocks the viruses being expelled on their breath.

However, European researchers have suggested these may not be effective and up to 90 per cent of particles can make their way through the fabric.

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 (e.g. scarves) are proposed as a last-resort interim solution by the US CDC until availability of standard PPE is restored.'