Covering up to escape: should we mask up in the fight against Coronavirus?

Whenever I used to see someone in a face mask – usually hailing from a country a long way from my own, I felt slightly offended. There’s nothing wrong with our air, I thought, defensively; wrongly, as I sat in a traffic jam next to the River Medway in Maidstone, Kent perhaps a year ago as I watched a masked young woman make her way along the towpath. I’d always seen the wearing of face masks in places like Tokyo as a sort of weird idiosyncrasy – a paranoia. I hadn’t realised that mask-wearing was really more of an act of solidarity – of kindness from a person who desired to protect others from whatever ailed them. Mask wearing was actually an act of duty towards others. 

Early adopter mask-wearing societies are faring better

It turns out that this behaviour has seemed to be quite protective within the societies that adopted the practice years ago. Chris Kenyon, at the Institute of Tropical Medicine in Antwerp, Belgium, has concluded that the spread of Covid-19 has been controlled more carefully in countries where they were early-adopters of masks against the virus. His pre-print (i.e. not yet peer-reviewed) has revealed that mask use in China, Czechia, Hong Kong, Japan, Singapore, South Korea, Thailand and Malaysia “reduce[d] the transmission and acquisition of respiratory viral infections”: https://www.medrxiv.org/content/10.1101/2020.03.31.20048652v1

The UK government has seemed reticent until recent days to officially advise the use of face masks, stating three prime reasons they do not yet recommend them for general public use. The first is possibly the most controversial and hinges on the availability of Personal Protective Equipment (PPE) for medical professionals. They are concerned that purchase of medical-grade masks will mean an even greater dearth of availability in masks for healthcare and keyworker staff who need them. 

Futhermore, the government have aired concerns on a psychological basis – that face-mask wearing may embolden the wearer and give a false sense of security, meaning they fail to adhere to social distancing practices. Finally, they say that the evidence on using face masks is not clear that it is even worth wearing and they point to the difficulties involved in ‘doffing and donning’ masks and other protective gear. They raise the idea that many will not know how to wear them safely and that improper use of the masks could mean a greater risk of infection to the wearer.

A 60 year old man wears a home-made, "no-sew" mask made in order to safely visit a Cancer ward for essential blood tests
A 60 year old man wears a home-made, “no-sew” mask made in order to safely visit a Cancer ward for essential blood tests

So what’s the scientific evidence on wearing face masks?

In order to understand why a face mask might help, one needs to comprehend the mechanism of transmission from an infected person. Currently, our social distancing rules on keeping 2 metres from every other person we do not live with is based on the distance it takes to transmit the virus. An infected person will spread the virus through their ‘respiratory emissions’ – that is the liquid droplets produced during coughs, sneezes and sometimes just from spittle that emerges during normal conversation. One cough, it is estimated, produces up to 3,000 droplets, all infused with the virus. Even speaking to one another means we “spray it, don’t say it”, in a twisting of the saying meant to call attention to someone’s tendency to overemphasise with saliva when they talk. 

Large droplets of saliva, mixed with the deadly virus, will land on surfaces nearby. Some on your clothes if you’re nearby. Predictions on how long Covid-19 lasts on surfaces differ, but it’s hard to know how many are being infected by surface transmission. What’s far more likely, though, it seems, is that the smaller droplets can remain suspended in the air. 

Who does mask-wearing protect?

Back to mask-wearing then. Does mask wearing protect the person who wears the mask? Or just everyone else? Initial evidence suggests that it’s not really about protecting yourself from it – that’s not what mask-wearing has really ever been about in a non-medical setting. It’s about reducing the transmission (called source control). Given that Coronavirus is known to have a long incubation time (hence the quarantine time of 14 days), you won’t know you have it for some time after you have already been infectious. Operating on the basis that you are always potentially a carrier and spreader is wise. 

The University of Hong Kong’s head of Epidemiology, Ben Cowley, looked at surgical masks in particular and determined that they could significantly reduce the transmission of various respiratory illnesses by reducing the distance a sneeze or a cough can travel: https://www.nature.com/articles/s41591-020-0843-2

Jeremy Howard, of the University of San Francisco, recently came head to head on television with Robert Peston and said he disagreed with Health Secretary Matt Hancock on the utility of cloth face masks for the general public. When asked to justify why, he said; “because I’m a scientist who just led the world’s first cross-disciplinary, international review of the evidence”. Quite qualified to disagree, then, it would seem. 

Indeed, the review, which you can read here, https://www.preprints.org/manuscript/202004.0203/v1 involved 19 authors and 84 citations of other studies, making it a huge piece of work on the efficacy of mask-wearing. A break-down of the study, designed for non-technical, lay-people has been prepared by Howard along with British doctor, Trisha Greenhalgh, who has been a stellar person to follow on Twitter on this subject. You can read that here: https://www.fast.ai/2020/04/13/masks-summary/

The conclusion from that epic review is that “source control” – stopping the spread from infected people – is the key to slowing down this virus rather than measures to protect the non-infected from getting it. They concluded “If you have COVID-19 and cough on someone from 8 inches away, wearing a cotton mask will reduce the amount of virus you transmit to that person by over 90%, and is even more effective than a surgical mask.”

Home economics: making your own mask

Whether you choose to make your own mask or buy one, it’s becoming clear that mask wearing is going to become more and more commonplace within our societies. Many work at home, cottage industry makers are benefiting from the increase in interest in masks and unexpected providers – like vistaprint – are allowing the customisation. If you are going to make your own mask, you don’t necessarily need a sewing machine or the knowledge of how to use one. There are various guides online – some using an added filter (sometimes fashioned from vacuum cleaner filters). What is more essential, however, is understanding how to wear them and how to remove them as well as disposing of them or reusing them. 

It’s recommended that cloth masks are washed at a temperature of at least 60 degrees C, so check the fabric you plan to use carefully for how hot it can go. Elastic can perish at high temperatures, which might also affect the longevity of your mask. The Center for Disease Control (US-based) has an especially helpful article on wearing, making and caring for your cloth mask: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html

Touching your mask while you’re wearing it is pointless, as is pulling it down beneath your chin to use your mouth to eat, drink, kiss or smoke (or any other purpose you can think of!) as the outside could, of course, be contaminated with virus. It’s important to understand proper mask wearing “etiquette” to prevent it becoming more of an infection risk. For a brilliant video on proper mask wearing behaviour, you can’t go wrong watching my diagnostic radiographer friend, Trish Hann explain all on the Guardian: https://www.theguardian.com/world/video/2020/mar/31/how-to-correctly-wear-your-coronavirus-face-mask-and-gloves-video

The UK’s political stance is a-changing

The message from the British government does seem to be turning, however – on his return to work after his battle with the illness, Boris Johnson suggested that mask-wearing could be a way back to some level of normality. 

Speaking on Thursday 30th April, he said: “What I think SAGE is saying, what I certainly agree with, is that as part of coming out of the lockdown, I do think face coverings will be useful […] Both for epidemiological reasons but, also, for giving people confidence that they can go back to work. You’re going to be hearing more about that and that kind of thing next week.”

We won’t know the exact timetable for lifting of lockdown measures and how we can fire up the economy again until Sunday. The pronouncement was initially due to come tomorrow, 7th May, but many suspect that this was rearranged to prevent non-compliance with lockdown over the predicted sunny Bank Holiday weekend on 8th -10th May. 

However much the government insists that they are led by the science, this excuse no longer holds water. “Science” isn’t one piece of advice and it doesn’t really change so much as it evolves. What’s clear now is that scientists are the ones in the firing line where mistakes are involved. Let’s just hope this government’s lethally slow response to Coronavirus is finally unmasked and we get truly evidence-based policy on Sunday. 

 

 

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