Masks: do they work?

Back at the start of the pandemic, England’s Chief Medical Officer, Chris Witty, and his US counterpart Anthony Fauci had this to say about wearing face coverings:

In terms of wearing a mask, our advice is clear: that wearing a mask if you don’t have an infection reduces the risk almost not at all. So we do not advise that. (Witty, February 2020)

There’s no reason to be walking around with a mask. (Fauci, March 2020)

The World Health Organisation was still saying in December 2020 that,

the use of a mask alone, even when correctly used, is insufficient to provide an adequate level of protection for an uninfected individual or prevent onward transmission from an infected individual. (Google ‘Mask use in the context of COVID-19’.)

While in February this year, The European Centre for Disease Prevention and Control (ECDC) concluded that,

Evidence for the effectiveness of non-medical face masks, face shields/visors and respirators in the community is scarce and of very low certainty.’

Why did experts like Witty and Fauci say initially that masks were inadequate, only later to change their minds? Because, I would venture to say that they were aware of the scientific studies, carried out prior to Covid-19, about masks’ effectiveness in preventing the passage of other SARS viruses, including influenza. At best, these concluded that even wearing surgical masks, as opposed to the supermarket varieties, has a limited effect on the transmission of either influenza or Covid. This is hardly surprising when the average distance between strands of fabric in a mask is between 5 – 200 micrometers, while the virus is 0.1 micrometers in diameter. In other words, the gaps in the fabric are between 500 and 2000 times larger than the virus. (Though this article argues that there is still a chance such masks can stop some transmission of the virus).

Other studies seem to bear out the limited nature of masks’ effectiveness. This one, by the University of Waterloo in Canada, concluded that masks filter only 10% of the airborne virus and that moderate ventilation offers better protection.

Similarly, The National Center of Biotechnology Information found that

There is uncertainty about the effects of face masks… The pooled results of randomised trials did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks during seasonal influenza.’

The Influenza Journal, reviewing 17 studies on mask wearing, said,

None of the studies established a conclusive relationship between mask/respirator use and protection against influenza.

The British Medical Journal (BMJ) advised that healthcare workers,

should not use cloth masks as protection against respiratory infection. Cloth masks resulted in significantly higher rates of infection than medical masks, and also performed worse than the control…

(More studies are cited here.)

Specific to Covid is this study from Denmark which examined how far masks protect the wearer from infection (it did not seek to discover the extent to which they might prevent the spread of the virus to others.) It reported:

Infection with SARS-CoV-2 occurred in 42 participants (with) recommended masks (1.8%) and 53 non-mask wearing (2.1%). Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection (my emphasis.)

The report suggested that social distancing was as likely to have caused the small reduction in infection rates.

While it is anecdotal, it was my experience that once mask wearing was mandated in the UK, people started to ignore social distancing measures, on the assumption, presumably, that everyone was safe behind their masks. Moreover, as the BMJ and others have pointed out, there is also evidence that mask wearing can be detrimental to one’s physical and mental health. And then there are all those discarded masks, infested with bacteria and virus particles that thoughtless numpties leave on the street for someone else to have to deal with.

So, why did the various experts and organisations change their minds about masks? Was it because more data became available about their efficacy? Unfortunately not. Instead, mask wearing became both politicised and polarised. As journalist Laura Dodsworth points out in A State Of Fear, face coverings became a means of social control and of giving us all a false sense of security (p113). It was and is wrong for politicians to mandate either the wearing or not wearing of masks. If people find some psychological reassurance from wearing them they should be able to do so. Those who don’t should not have to. In the UK, where indoor mask wearing was mandatory only up to July 19th, there has been a sharp decrease in mask wearing with only a small increase in hospitalisations due to Covid. (These admissions are not necessarily the result of less mask wearing; mass social events have returned during this period.) I have rarely worn a mask since July (only when asked, in fact) with no ill effect for myself or others. I’m trusting in the vaccine and other preventative measures. As the ECDC said in February:

the use of face masks in the community should complement and not replace other preventive measures such as physical distancing, staying home when ill, teleworking if possible, respiratory etiquette, meticulous hand hygiene and avoiding touching the face, nose, eyes and mouth.

It is these other measures that minimise the chances of contracting or spreading the infection, not face coverings. It is beggars belief that we had to be told, and taught how, to wash our hands once the virus took hold. That daintily expressed ‘respiratory etiquette’ is important too. I would advocate regular face washing followed by nose-blowing into a tissue; while I’ve no evidence for it, I feel sure these have prevented me from getting colds and flu for most of my life. Physical distancing remains an important measure, though large gatherings make it difficult to achieve; in such circumstances masks might compensate to a limited extent by providing some small degree of protection  

So, masks: do they work? It looks like they don’t, not to any significant degree anyway. Let me give the final word to a doctor whose letter was published in The Daily Telegraph last week:

SIR – A paper published in 2016 by the American National Institutes of Health reviewed previous clinical trials of the use of face masks in operating theatres. It concluded: “Wearing a face mask neither increases nor decreases the number of wound infections following surgical operations.”

A simple experiment will show why: if a lighted candle is held in front of a mask the flame cannot be extinguished, no matter how hard one blows. However, if the candle is held to the side of the mask it is easily extinguished.

Moreover, the obstruction of exhaled air by the mask increases its pressure and the distance it will travel.

Hence the wearing of a mask will increase the area in which the exhaled air is dispersed. In this context it is interesting that in one clinical trial a slight but not statistically significant increase in infections was associated with the wearing of masks.

There simply is no sound scientific evidence for the wearing of masks to prevent transmission of infections. On the other hand, a controlled trial is not required to show their dehumanising effect.

Dr Max Gammon

London SE16