Mask wearing has been a consistent point of controversy during the COVID-19 pandemic. During the early stages of the coronavirus outbreak we saw health agencies advising people that wearing masks was ineffective, but in the last few days the CDC has changed their tune. This has been a confusing topic, so it is worth looking at some of the literature on this topic.
Of the work that has been written on COVID-19 and masks, one of the most influential papers was a letter published by Feng et al. in the Lancet on March 20th. This short letter is actually quite interesting, as it makes the case for universal mask wearing using mainly a logical argument, rather than looking at data.
To understand this letter it is first important to recognize that there had not yet been any substantial study results covering the use of masks in the COVID-19 pandemic. The type of research is relatively time consuming. The discussion was based on previous literature on other viruses, and best guesses from experts based on the limited data available at the time.
An important divide they address is the need for N95 respirators for healthcare workers. Doctors and nurses need high quality masks to do their jobs without being infected, so all N95 masks (and surgical masks if N95 are not available) should go to this group as long as they have a need. Aside from this, the authors suggest that people should be wearing masks, even though there is no clear evidence that wearing masks stops people from contracting COVID-19.
There are two interesting logical moves here. First, it makes clear that healthcare workers should get sufficient masks to do their job, and the question of whether the public should wear them is separate. It has been surprisingly hard for health agencies to articulate this distinction. Early “mask discourse” seemed unwilling to discuss the use of masks outside of doctors and nurses, as many were paranoid that there would be a run on N95 respirators.
On the second point, there is more nuance necessary. The authors make is clear that while there is no evidence that face masks stop catching a disease like COVID-19, there is also no clear evidence that wearing a face mask COVID-19 doesn’t stop disease. That is to say “there is no proof that masks don’t work”. It seems logically intuitive that masks (even cloth ones) would limit the spread of disease, so why not use them? In addition, masks do prevent sick people from spreading other viruses, so it makes sense to normalize the behavior of mask wearing. It is likely that mask wearing will be more effective at stopping people from spreading the disease rather than stopping people from catching the disease, but that is still a good thing! Not only that, when people wear masks it normalizes other people wearing masks, encouraging good habits among others.
The authors do make it very clear that more research is necessary, but it is also clear that we can’t always wait for the science in a pandemic. This letter, and other comments like this, seem to have been enough to push organizations like the CDC to change their recommendations, and encourage mask wearing. It is fascinating to see good reasoning be used in this manner, as it is rare that scientists put out a letter like this without hard data. Nevertheless, this was a very useful contribution to the discourse.
This is part of a series on preliminary research that relate to the COVID-19 pandemic. As this covers papers that are not finalized in an area of study that is evolving rapidly, it is possible that some of this research will end up being modified, and should be taken as such. Other articles in this series cover hydroxychloroquine, weather’s effect on COVID-19, and airborne transmission.
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