Please note: I am not a medical doctor. You should refer to the medical studies presented below for expert medical advice.

[If you’re here for the mask pattern and instructions, skip to “How can source a cheap mask without reducing the supply for medical professionals?” – but don’t forget to read up on how to fit and discard/sterilize your mask properly.]

Why wear a mask?

1. Most importantly, to help others. Coronavirus is spread by droplets, for example, in your coughs or sneezes. Masks provide a physical barrier to help prevent others from becoming infected. They can help trap large particles, like bodily fluids (saliva etc.) which may contain viruses.

2. To a lesser extent, to help yourself. David Hui is a respiratory medicine expert at the Chinese University of Hong Kong who studied SARS extensively. He says “If you are standing in front of someone who is sick, the mask will give some protection”. “The mask provides a barrier from respiratory droplets, which is predominantly how the virus spreads.”

A number of studies show the efficacy of face masks in reducing the transmission of influenza-like illnesses. (See bottom of the page for details, or check out this comprehensive video):

Furthermore, a BBC report suggests that even if masks won’t fully protect you from aerosol droplets in the air you breathe, they can also play an important role in reducing hand-to-mouth transmission, which can happen when you touch an infected surface, and then inadvertently touch your mouth.

Shouldn’t I only wear a mask if I’m sick?

As the CDC reports, it appears possible to spread the virus before you experience any symptoms. The delay between becoming infected by a virus and developing symptoms is known as the ‘incubation’ period. For COVID-19, the WHO estimates the incubation period is between 1 and 14 days.

So it appears possible to spread the virus for up to two weeks before you feel unwell. Yet, the WHO, and many governments have cautioned against the use of face masks by healthy people. In large part, this seems to be in order to preserve the supply for those who need them most. Healthcare workers and those diagnosed with the virus. Not because it doesn’t help.

Worldwide, equipment shortages have forced some medical professionals to reduce the number of patients they help. Or, to risk exposure themselves, with tragically high numbers of doctors and nurses contracting coronavirus in numerous countries. “If you are not ill or looking after someone who is ill”, says the WHO, “then you are wasting a mask”. That being said, there are many places in which mask use by the general public is normal. In some, it is even required, with countries making masks mandatory in public. (See bottom of the page for details).

Isn’t this what social distancing is for?

Around the world, people are being advised to stand 1, 1.5, even 2 meters apart from each other. While this advice is helpful, it is difficult to enforce in crowded urban settings. Additionally, a recent opinion piece in the BMJ suggests that this advice is based on two studies published 80 years ago, and more recent evidence suggests droplets can travel further than two meters. So social distancing alone will not completely stem the spread.

Furthermore, many coronavirus transmissions are household-based rather than between households. Social distancing may be impossible for those who do not have the luxury of large houses. But masks can be worn by household members unable to distance themselves. (Indeed, this is a part of the WHO protocol for reducing household transmission).

But I heard masks don’t work!

Some – including the US Surgeon General – have tweeted and otherwise made discouraging noises about masks, stating that they are “not effective”.

But as David Hui points out, a lack of solid evidence for the prevention of a specific virus like COVID-19 is no reason to dismiss the use of masks, because there may never be definitive scientific proof. Why? Simply put, it is impossible to conduct a properly controlled study in an ethical manner. “You can’t randomize people not to wear a mask, and some to wear a mask, and then expose them all to the virus” he says. Furthermore, as mentioned above (and cited more fully at the bottom of this article), quite a number of studies have shown that, when actually utilized, and combined with hand washing, masks can be very effective in dramatically slowing the spread of influenza-like illnesses.

Further examination of the Surgeon General’s tweet shows the issue at hand is, once again, one of supply. Not one of believed efficacy. It continues, ‘if healthcare providers can’t get them to care for sick patients, it puts them and our communities at risk’.

Think about it: if masks weren’t effective, why would healthcare providers need them?

The WHO clearly states that “Wearing a medical mask is one of the prevention measures to limit spread of certain respiratory diseases, including 2019-nCoV” However, it also cautions that wearing masks “when not indicated may cause unnecessary cost, procurement burden, and create a false sense of security”. (Emphasis added). In other words, the issues are to do with price, supply, and people not following other important directives, like hand washing. None of the issues raised are health problems. We can eliminate the issues presented so long as we can find a mask that:

doesn’t cost a lot

doesn’t take supply away from those who need it most

is worn with full understanding of the limitations of masks and how best to utilise them

How can I source an affordable mask without reducing the supply for medical professionals?

Even if you don’t care about the supply of masks for healthcare, or about their environmental impact, chances are, you couldn’t find a surgical mask to buy at this point even if you wanted to. Some major manufacturers have banned exports in order to meet their own domestic needs. Those masks which are being produced are required by those risking their lives to help us. Demand has been so strong thieves have robbed cancer hospitals. And online retail platforms have banned mask sales thanks to obscene price gouging. In some regions, whenever a new shipment of masks comes in, the lines to get a pack are massive. Meaning social distancing goes out the window.

Science to the rescue!

Thankfully, scientists in Hong Kong have devised a cheap, easy way to make home-made masks. They are biodegradable, and save the professionally manufactured PPE for those who most need it. In laboratory tests conducted at City University, these home made masks were 80-90% as effective as regular surgical masks in terms of their filtration of aerosol and droplets.

For those who want a more robust option, or who are concerned about the social stigma of wearing a mask (let alone a homemade one), Dr. Kenneth Kwong of the HK MASK project has devised a reusable mask with replaceable filters to tackle the shortage of surgical masks in Hong Kong.

We have come up with a pattern to stitch your own. (Thanks to my mother, the talented seamstress, for reverse-engineering the commercial, form-fitting masks we bought in Taiwan, and my husband, for drafting the pattern) And, you can use the layered paper towel and tissues suggested by the Hong Kong scientists in the video above as disposable filters. You’ll need

cotton fabric (patterned for the outside if desired, and some plain),

(patterned for the outside if desired, and some plain), elastic (at least 40cm per mask),

(at least 40cm per mask), and tie wire (7cm per mask). If you can’t find tie wire, then strong twist ties may work, the nose piece from another mask.

(7cm per mask). If you can’t find tie wire, then strong twist ties may work, the nose piece from another mask. (For the disposable filters: 1 piece of kitchen paper (halved) and 1 tissue, per mask, per use)

Here’s how to make it:

Preparing the fabric: Print the pattern at full size and cut out the necessary shapes. You’ll need 2 of the large mask shapes cut out of the patterned material, plus 2 of the same shape for the lining. Then, cut a further 2 pieces of the lining material with a shallower curve (the dotted line). These will be used to make an inner pocket. You will also need 2 tabs for holding the elastic. Preparing the nose piece: Cut a piece of tie wire (the plastic coated sort used for gardening) to 7cm. Turn back at the ends. If desired, paint the ends with nail polish to prevent rust. Leave to dry while you construct the mask. Sewing the mask: Piece the two large mask shapes together, patterned side in. Overlock or stitch down the curve (If you stitch, you will need to clip the hem of the curve). Topstitch if desired. Then, do the same for the lining material (not the pocket pieces). Overlock or hem the curved section of each of the pocket pieces. Place the pocket pieces one on top of the other. Stitch along the curve approximately 2cm either end. You need to leave an opening in the middle so you can insert the disposable filter papers later. Place the outer piece (patterned side up) on a flat surface. Then, place the pocket pieces on top, followed by the lining piece (seam side up). Pin, and overlock the top and bottom (long sides). Turn inside out so that the pattern is at the front and the pocket is at the back. The lining should now be in the middle. Now stitch the sides. Tab: Overlock, press and hem the top and bottom (short side). Fold in half and overlock or stitch into a tube. Stitch onto the sides of the mask. Nose piece: Using the zipper foot, stitch a line 7cm long approximately 1cm below the top of the mask to fit the wire in. Stitch up one side. Place the wire piece inside (access through the pocket). Elastic: Cut two pieces of elastic approximately 20cm long. Thread elastic through the holders and knot to desired length. Try the mask on and adjust the nose piece and, if necessary, the length of the elastic. Before use, insert a filter constructed from a folded piece of kitchen towel and a tissue. (As instructed in the video above.)

(Picture guide coming soon)

What do I need to be careful of?

A mask alone is insufficient.

Many of the cautions about mask use highlight the fact that simply wearing a mask is not enough. As WebMD summarises, “the biggest concern that doctors have around recommending masks is the false sense of security that might come along with wearing one”.

The WHO states that “Wearing a medical mask is one of the prevention measures to limit spread of certain respiratory diseases, including 2019-nCoV”, but warns “the use of a mask alone is insufficient to provide the adequate level of protection and other equally relevant measures should be adopted. If masks are to be used, this measure must be combined with hand hygiene and other infection prevention and control measures”.

It’s hugely important for everyone to maintain good hand hygiene. In situations where contact with an infected person is likely, use glasses or a face shield as well.

Yet, as one BMJ opinion piece argues, “insufficient” does not mean of “no use.” The fact that a healthy diet alone won’t prevent heart attacks doesn’t mean we should not eat well.

Your mask needs to fit.

The better it fits, the better it works. Additionally, if your mask is uncomfortable, chances are, you’ll wind up touching it. And increasing your exposure.

The mask pattern above is designed to fit under your chin, secure firmly across your face via elastic, and to fit well around the nose by pinching the wire to the correct shape.

You need to dispose of/sterilize it correctly.

It’s important to follow the WHO advice on putting on and removing your mask.

If you have a disposable mask, you should also read their advice on throwing it away safely.

Alternatively, if you have a reusable mask, remove the mask and carefully dispose of the filter. Then, HK MASK recommends sterilizing the outer cloth jacket at a high temperature. This must be done every time you use the mask. (You may find it useful to have multiple masks for this purpose). Live Science recommends steaming in water vapor for 10 min.

WARNING: DO NOT microwave masks with wire! It will start a fire!

A mask is supposed to prevent you getting sick and breathing in (or out) dirty air. The last thing you want to do is wear a mask that is harboring disease. Thoroughly sterilize and wash your mask regularly.

#Masks4All

What evidence supports mask use?

Mega List: Jeremy Howard and Reshama Shaikh’s Collection

Masks work – if you wear them.

In response the number of countries stockpiling face masks to reduce viral transmission during a pandemic, a study was carried out in 2009 to examine the efficacy of masks in reducing the transmission of influenza-like illnesses. The research involved 286 adults from 143 households who had been exposed to a child with clinical respiratory illness. The study found no significant difference in risk of illness between the mask and no mask groups. However, the researchers found that fewer than 50% of those who were given masks reported actually wearing them most of the time. Among those who actually wore the masks, there was a significantly-reduced risk of infection.

In simple terms: just like condoms, masks can be effective in preventing transmission – but only if you actually wear them. The researchers concluded that household use of masks was associated with low adherence, making them ineffective in controlling seasonal flu, but “mask use might reduce transmission during a severe influenza pandemic” when people take mask use more seriously.

Masks + Hand Hygiene = a winning combination

Another 2009 study conducted in Hong Kong involved 407 patients with influenza-like illnesses in 259 households. It compared lifestyle education (control group), hand hygiene advice, and hand hygiene + surgical face masks. After one week, 8% of those patients’ household contacts had confirmed influenza infections. Hand hygiene seemed to reduce transmission, but not significantly. However, “hand hygiene with facemasks seemed to prevent household transmission of influenza virus when implemented within 36 hours of index patient symptom onset”. The researchers concluded that such interventions “are important for mitigation of pandemic and interpandemic influenza.”

A similar study carried out in America in 2010 compared the effectiveness of education, education + hand sanitizer, and education, hand sanitizer + masks against upper respiratory infections and influenza in crowded, urban households. It found that although there was no detectable benefit of using masks or hand sanitizer over targeted education in the 509 households participating, mask use was associated with reduced secondary transmission. The researchers concluded that mask wearing “should be encouraged during outbreak situations”.

Another 2010 study, taking into account the lack of a vaccine and the limitations of treatments during the A(H1N1) pandemic, also investigated the use of face masks and hand hygiene. The randomized trial assigned 1437 young adults living at university residence halls to three groups: mask-use, masks with hand hygiene, and control (neither), following them over a 6 week period. Significant reductions in influenza-like illnesses were observed in weeks 4-6 in the mask and hand hygiene group compared to the control group. Face mask use alone also showed a reduction, but not a statistically significant one. The authors concluded that “face masks and hand hygiene may reduce respiratory illnesses in shared living settings and mitigate the impact of the influenza A(H1N1) pandemic.”

In 2012 a group of researchers conducted a trial among 1,178 young adults at university halls during influenza season. They were assigned to face mask + hand hygiene, face mask only, and control groups. The researchers found a reduction in influenza-like illnesses among students using these measures. They concluded “masks and hand hygiene combined may reduce the rate of ILI (influenza-like illnesses) and confirmed influenza in community settings. These non-pharmaceutical measures should be recommended in crowded settings at the start of an influenza pandemic.”

What is the rest of the world doing?

Wearing a mask is very common in many Asian countries, especially those which dealt with SARS in the past. Thus, it is unsurprising that people across Asia have taken masks seriously with the coronavirus outbreak. Authorities in South Korea, Singapore, and Japan have distributed masks to their residents.

South Korean, Singaporean and Japanese authorities have distributed face masks to their residents, and Taiwanese and Thai governments have banned exports to meet local demands. Chinese authorities also recommended the public wear masks, this recommendation featuring in Chinese expert volunteers’ advice to Italy.

The cultural divide

Wearing a mask in most Asian countries does not automatically mean you are sick. It may mean that you have hayfever. That you don’t want to get sick. That you want to avoid smells, or dry air. Or, that you simply like how they look (masks are highly fashionable in many places).

Recently, there have been reports of racist attacks in countries such as Australia and the US. Asians have been spat at, called names, or even physically beaten, ostensibly for wearing a mask.

In spite of these prejudices, the message about masks appears to be spreading. People can now be seen wearing masks across Australia, Europe, the Americas, and elsewhere. And in some places, it is becoming official policy. Slovakia has recently made mask wearing compulsory for anyone who wants to go outside (English summary).