The recent back and forth debate – and policy reversal – about using face masks to prevent the spread of Covid-19 shows a blatant double standard. For some reason, we've treated this one public health issue differently. We don't see comments that ask whether people on the street really need to be 6 feet apart from 3 feet, or raise doubts as to whether it is such a good idea to encourage handwashing for 20 seconds. But when it comes to covering our faces, scientific hyper-rigor has been applied. In recent weeks, experts have been cautious ̵
You are of course right that the research literature on mask use does not. t give definitive answers. There are no large-scale clinical studies showing that personal use of masks can prevent a pandemic from spreading. and those dealing with masks and influenza have had ambiguous results. But this little evidence doesn't tell us much at all: the experiments neither prove that masks are useful, nor that they are dangerous or a waste of time. This is due to the fact that the number of studies was both small and had methodological problems.
Take, for example, a large randomized study of mask use among US college students in the 2006/07 influenza season. The reduction in disease in people wearing face masks in this study was not statistically significant. However, because the study was carried out during a mild season for the flu, the study lacked statistical significance for this question. There weren't enough sick people for researchers to find out whether wearing masks alone improved hand hygiene. They also could not rule out that students were infected before the study started.
Or another study of the same influenza season, this time in Australia, which had no final effect. This looked at adults who lived with children who had influenza. Less than half of those randomized to the mask wearer group said they used "almost or all of the time". In fact, they often slept alongside their sick children without them. This has little in common with the question of whether you should wear a mask among strangers in the grocery store in the middle of a pandemic.
But here's the thing: you could make the same complaints about the evidence that masks are used by healthcare workers too. Everyone agrees that this practice is absolutely critical in hospitals and clinics, but that's not because we have convincing evidence from randomized trials. The few clinical studies in which we use masks for healthcare workers to prevent influenza do not have a clear effect. Neither can they prove that the larger N95 respirators work better than surgical masks. These attempts are also far from ideal. For example, the effectiveness of fabric masks was tested by comparing healthcare workers who wore them to those who wore surgical masks or respirators, and a control group that followed "standard practice" in the hospital. It turned out that the majority of the workers in the control group wore surgical masks anyway, so the study couldn't really show whether the fabric masks were better (or worse) than no masks at all.
In fact, the science foundation for healthcare workers who use masks are not clinical trials on influenza outbreaks or pandemics. It comes from laboratory simulations that show that masks can prevent the entry of virus particles – there are at least a few dozen of them – and from case-control studies during the 2003 Coronavirus epidemic that caused SARS. These SARS studies were not limited to healthcare workers.
It is true that healthcare workers or others caring for people with Covid-19 are exposed to a much higher level of coronavirus than anyone else. In the context of a mask deficiency, they obviously have a priority claim to access. However, this is no reason to believe that the use of masks is not supported by everyone else. After all, as far as we know, there are no clinical studies showing that a social distance of 6 feet prevents infection. (The World Health Organization only recommends a 3-foot separation.) Clinical studies also don't show that washing our hands for 20 seconds is superior to washing 10 seconds when it comes to spreading disease in a respiratory pandemic to limit. The scientific basis for this 20-second hand wash council from the United States Centers for Disease Control and Prevention is laboratory studies, in which viruses on the hands were measured after different washing times.
So where did this double standard regarding face masks come from – and why was it finally dropped?
I think this is mainly because we have repeatedly underestimated this virus and at the same time overestimated our own ability to deal with it. Miao Hua, anthropologist and medical worker at Mount Sinai Hospital in New York City, was shocked by the different attitudes towards infection control in the United States compared to Wuhan. In China, she wrote a few weeks ago, the proliferation in hospitals quickly suppressed the idea that routine containment strategies would be enough to stop this new coronavirus. What she heard from China was surreal, she said, and particularly worrying given the "failure of the American medical community to register the historical uniqueness of Covid-19."
The recent change in CDC mask support policy suggests this – an overdue confirmation may have been made. The agency's statement attributes the change to the accumulation of evidence that the disease is not transmitted in the same way as influenza: that people can be contagious and asymptomatic, and that the virus spreads through speaking, coughing, sneezing, and contacting can contaminated surfaces.
I think the reluctance to encourage the use of masks by the general public, as well as the use of a double standard to support evidence, have also been driven by concerns that people could not use masks without themselves contaminate themselves. Or that masks convey a false sense of security and lead to social distances or other measures easing. However, effective communication is the key here, just like a thorough hand washing technique. Stella Quah, sociologist at the University of Singapore, examined the social aspects of the SARS epidemic in Singapore. The public health campaign included hand hygiene education, temperature measurement and the correct use of face masks. The CDC reversed its face mask guide last Friday and then released some limited advice on how to wear and remove it, as well as instructions on how to make your own from a combination of bandanas and coffee filters.