Why wearing a mask works so well in China — and how you can easily make one at home Nikita Sokolsky Follow Mar 22 · 9 min read

If you’ve been following the news about the coronavirus epidemic in the West, you’ve probably heard that wearing masks doesn’t protect you against the disease. The WHO says so:

If you are healthy, you only need to wear a mask if you are taking care of a person with suspected 2019-nCoV infection.

The CDC says so:

If you are NOT sick: You do not need to wear a facemask unless you are caring for someone who is sick (and they are not able to wear a facemask). Facemasks may be in short supply and they should be saved for caregivers.

The Canadian government says so:

There is no evidence on the usefulness of face masks worn by healthy / asymptomatic persons as a mitigation measure, therefore it is not recommended. Globally masks are in short supply and the current demand for masks cannot be met; therefore, appropriate use of face masks should be encouraged.

And the UK government says so:

Face masks play a very important role in clinical settings, such as hospitals but there’s very little evidence of widespread benefit from their use outside of these clinical settings. Facemasks must be worn correctly, changed frequently, removed properly and disposed of safely in order to be effective.

We can therefore see three arguments against wearing a mask:

They’re not effective at preventing you from breathing in the virus, as the mask is not airtight Even if the mask is airtight, the public lacks the knowledge on how to use one properly If everyone buys a mask, there won’t be enough left for the hospitals

With those arguments in mind, let’s take a look at what countries that are ahead of the epidemic curve doing in the effort to tackle COVID-19: China and South Korea.

China

Back on January 22nd when the epidemic was nearing it’s peak in Wuhan, authorities made them mandatory to wear in public:

It is now mandatory to wear face masks in public places in Wuhan, the Chinese city where the new coronavirus emerged last month. Wuhan’s municipal government published a notice on Wednesday, stating that all public places are to require customers to wear masks and owners are to prevent people from entering if they are not.

On January 31st it was reported that China started using drones to call out people who aren’t wearing a mask. Looking at post-epidemic pictures from China we can see that their senior leaders are always wearing masks:

President Xi Jinping is briefed during a visit to a hospital in Wuhan in 2020 © Xie Huanchi/Xinhua/AP

This cannot be explained by the general popularity of face masks in South East Asia — formerly they were primarily used to protect oneself against pollution and Chinese politicians rarely showed in public wearing one.

Chinese Vice-President Wang Qishan shakes hands with President Xi Jinping in 2018. © Reuters/Jason Lee

South Korea

In Seoul, the government was more proactive than others given their experience with the SARS outbreak in 2003, so they were able to contain the outbreak without a full scale shutdown. However they too recommend wearing a mask in public:

What should I do prevent infection? Strictly observe personal hygiene rules such as wearing a mask, washing hands, and covering your mouth and nose with an upper sleeve when coughing).

This recommendation is in place despite the fact that a mask shortage exists in South Korea, just like in the West:

South Korea began rationing face masks on Monday to cope with a severe shortage among the public as the nation scrambles to contain the spread of the coronavirus that has infected nearly 7,400 people.

The South Korean government likewise wears a mask in public, at least some of the time:

President Moon Jae-in in Daegu, the epicentre of his country’s coronavirus outbreak © AP/Han Sang-kyun

Examples so far were dealing with South East Asian societies. Some claim that their usage of masks is a cultural phenomenon that cannot be replicated in the West. And statistically speaking facial masks were indeed very popular even before the current pandemic:

The rate of mask use in Japan has continued to increase. In the Kobayashi Medicine Company of 1200 Japanese citizens (Noguchi, 2011), 18% of participants reported that they wore masks on a daily basis in 2008, increasing to 26.2% in 2009, 27.7% in 2010, and 30.6% in 2011.

So let’s take a look at a European country that has virtually no cultural experience with wearing a mask.

Czech Republic

The very first coronavirus patients tested positive in Prague on March 1st and the government has been rapidly escalating their containment efforts since then. However initially their masks strategy was similar to the one recommended by the WHO. In a leaflet released by the National Institute of Public Health the government recommended against wearing one:

Masks are not recommended as protection from COVID-19. Healthy people do not need to wear masks unless they care for a person ill with COVID-19.

Things started to change on March 13th after the dean of the Czech Technical University created a manual on making your own mask out of a plastic bottle. It was impractical to wear, but inspired others to try their hand at creating a homemade mask.

On March 15th, a Facebook group titled “Czech Republic sews masks” was created and quickly became popular — as of March 21st it has 34k members. The group attracted thousands of citizens with a sewing machine who started distributing the masks around the country.

© Jakub Hruška; Canva, Pexels

On March 16th, popular TV host Leos Mares published a video asking citizens to cover their mouths and nose with any piece of fabric. The video was viewed 470k times and inspired a wave of celebrity mask endorsements. Merely a day later, Prague public transport banned passengers without a face mask. And finally on March 19th it became officially forbidden to go outside without putting on a mask, just like in Wuhan. The government likewise followed suit and started wearing masks in addition to maintaining physical distancing:

Press conference after the government meeting on the coronavirus situation. March 17th 2020 © ČTK

As we can see, the entire country went from rarely wearing a mask to everyone wearing one in just one week. It didn’t matter that Czechs weren’t used to the practice or that there weren’t enough surgical masks in store.

Other countries

Inspired by the Chinese and Czech success stories, masks became mandatory in Uzbekistan on March 23rd, with citizens likewise rushing to make millions of masks at home using their sewing machines. Similar measures are currently being considered in Slovakia, which changed its mask guidance in recent days.

Scientific studies

A lot of people might discount wearing masks as a security theater, so let’s take a look at what scientific research tells us. Luckily Petr Ludwig’s excellent video on homemade masks already did an excellent job of collecting the references.

1. Brienen, Nicole CJ, et al. “The effect of mask use on the spread of influenza during a pandemic”

We conclude that population-wide use of face masks could make an important contribution in delaying an influenza pandemic. Mask use also reduces the reproduction number, possibly even to levels sufficient for containing an influenza outbreak.

2. van der Sande, M., Teunis, P., & Sabel, R. “Professional and home-made face masks reduce exposure to respiratory infections among the general population”

Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection.

3. MacIntyre, C. R., Cauchemez, S., Dwyer, D. E., Seale, H., Cheung, P., Browne, G., … & Ferguson, N. “Face mask use and control of respiratory virus transmission in households”

We concluded that household use of face masks is associated with low adherence and is ineffective for controlling seasonal respiratory disease. However, during a severe pandemic when use of face masks might be greater, pandemic transmission in households could be reduced.

4. Davies, A., Thompson, K. A., Giri, K., Kafatos, G., Walker, J., & Bennett, A. “Testing the efficacy of homemade masks: would they protect in an influenza pandemic?”

The median-fit factor of the homemade masks was one-half that of the surgical masks. Both masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask. Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection.

5. Milton, Donald K et al. “Influenza virus aerosols in human exhaled breath: particle size, culturability, and effect of surgical masks”

Surgical masks nearly eliminated viral RNA detection in the coarse aerosol fraction with a 25 fold reduction in the number of viral copies, a statistically significant 2.8 fold reduction in copies detected in the fine aerosol fraction, and an overall statistically significant 3.4 fold reduction of viral copy number in the exhaled aerosols.

Dispelling the myths around face masks

We can now go back to WHO/CDC’s original arguments against wearing masks and explain their flaws.

“They won’t help against an infection” — yes, they won’t. But they will help contain the disease as most aerosols expelled by sick people will be contained within the mask. If everyone wears a mask they become extremely effective. “The public doesn’t know how to use a mask” — they most certainly don’t, but this is something that can be taught by governments and public figures. Czech Republic has proven that it’s possible to convince people to follow the right practices on a very short notice. “Public demand for masks will cause a shortage” — a shortage happened anyway as people were hoarding masks with or without governmental guidance. However it could be alleviated by asking members of the public to sew homemade masks — those will be mostly intended for casual wear and thus medical workers won’t be competing for protective gear with the general public. “There aren’t enough masks for everyone” — that is absolutely true for medical-grade masks and respirators. However homemade masks are extremely easy to make from common household goods and could be used until commercial mask factories expand sufficiently to meet the demand.

I’m convinced, now how do I get a mask?

1. First of all, if you at all can — stay home. Isolation is the best way of reducing transmission, even if masks help in that regard.

2. If you already have a bandana, a ski mask, a long scarf, or anything else that covers your mouth and nose — you can use that.

An Iranian woman covers her mouth with a scarf while wearing a plastic glove, following the coronavirus outbreak, as she walks in Tehran © Reuters

3. If you have a piece of cloth or paper towel, a stapler and a couple of rubber bands, you can make the simplest possible mask in just a few minutes.

4. If you own a sewing machine, you can make a reusable face mask as well. These could also be donated to local hospitals if they happen to run out of proper medical equipment.

5. Some countries now have volunteer organizations distributing homemade masks to those who need them — for example DameRousky.cz shows you locations where local sewers distribute homemade masks in Czech Republic.

Disposable face masks should be used once and then thrown in the trash. You should also remove and replace masks when they become moist. Reusable masks can be worn again after you wash and dry them.