(p. A19) The Evidence
From the beginning of the pandemic, there has been a paradox involving masks. As Dr. Shira Doron, an epidemiologist at Tufts Medical Center, puts it, “It is simultaneously true that masks work and mask mandates do not work.”
To start with the first half of the paradox: Masks reduce the spread of the Covid virus by preventing virus particles from traveling from one person’s nose or mouth into the air and infecting another person. Laboratory studies have repeatedly demonstrated the effect.
Given this, you would think that communities where mask-wearing has been more common would have had many fewer Covid infections. But that hasn’t been the case.
In U.S. cities where mask use has been more common, Covid has spread at a similar rate as in mask-resistant cities. Mask mandates in schools also seem to have done little to reduce the spread. Hong Kong, despite almost universal mask-wearing, recently endured one of the world’s worst Covid outbreaks.
Advocates of mandates sometimes argue that they do have a big effect even if it is not evident in populationwide data, because of how many other factors are at play. But this argument seems unpersuasive.
After all, the effect of vaccines on severe illness is blazingly obvious in the geographic data: Places with higher vaccination rates have suffered many fewer Covid deaths. The patterns are clear even though the world is a messy place, with many factors other than vaccines influencing Covid death rates.
Yet when you look at the data on mask-wearing — both before vaccines were available and after, as well as both in the U.S. and abroad — you struggle to see any patterns.
Almost 30 Percent
The idea that masks work better than mask mandates seems to defy logic. It inverts a notion connected to Aristotle’s writings: that the whole should be greater than the sum of the parts, not less.
The main explanation seems to be that the exceptions often end up mattering more than the rule. The Covid virus is so contagious that it can spread during brief times when people take off their masks, even when a mandate is in place.
For the full commentary see:
(Note: the headings appeared in bold in the original.)
(Note: the online version of the commentary has the date May 31, 2021, and has the title “Why Masks Work, but Mandates Haven’t.”