The authors of a recent New York Times op-ed describe universal masking as “one of the effective and efficient strategies for preventing SARS-CoV-2 transmission in schools”. And given the putative evidence supporting this measure, they ask rhetorically, “Why not require universal masking?”
The authors – a paediatrician and an epidemiologist – cite evidence from a recent study carried out in North Carolina. They collected data on COVID-19 infections among 864,515 students in the state’s school system from March 1st through June 25th, 2021. During this period, there was a mask mandate in place for all K-12 schools.
In total, 6,484 primary infections were recorded, and only 308 secondary infections. (Secondary infections refer to those among the contacts of students who were initially identified as infected.) “We believe this low rate of transmission occurred,” the authors write, because of universal masking.
By contrast, they note that “one school in Israel without a mask mandate… reported an outbreak of COVID-19 involving 153 students”. And “outbreaks at youth camps in Texas, Illinois and Florida show how quickly COVID-19 can spread among adolescents… who are largely unmasked”.
However, there are a number of problems with this argument. As you may have already noticed, there was no control group. The authors observed a low secondary attack rate, and then attributed this to the state’s mask mandate.
Yet infections were falling over the relevant time period in North Carolina as a whole. Only 390 cases were recorded on June 25th, compared to over 2,000 on March 2nd. And several previous studies have found “much lower” secondary attack rates among children, so it may not be that surprising the authors observed a low value.
As David Zweig notes, schools in some parts of Europe and the U.S. did not have mask mandates, and there were no corresponding explosions of cases. What’s more, the Israeli study isn’t as clear-cut as the authors suggest. All schools in the country were exempt from masks for three days, so a single outbreak isn’t strong evidence for mask efficacy.
But put all that to one side. Suppose the authors are correct that universal masking reduces transmission in schools. Is it therefore worth doing? I would argue no.
First, there are tangible costs to mask-wearing. They’re uncomfortable. They get dirty. And they don’t allow you to see other people’s faces, which hampers learning (particularly for the youngest children) as well as social interaction more generally.
Second, it’s not even clear that we want to prevent children from becoming infected. For starters, they face an extremely low risk of death from COVID-19. According to a recent English study, the survival rate for under-18s is 99.995%. And if COVID-19 becomes endemic, which seems very likely, they’ll have to get it at some point. So why not now?
In fact, we might want to encourage children to become infected, the better to build up population immunity and protect the most vulnerable. (I’m of course exempting children who have a serious underlying health condition.)
Vaccination is another option, but I believe we should focus vaccines on those who actually need them, such as elderly people in other countries. And in any case, many people don’t want their children to be vaccinated.
The authors of the New York Times piece make two claims: universal masking cuts transmission in schools; and therefore we should require it. I’m sceptical of the first claim, but even if it’s true, the second doesn’t follow. Wearing masks is costly, and it’s not even clear we want to prevent infections among healthy children.
Kids have already paid a heavy price during the pandemic, thanks to months of ill-advised school closures. Rather than forcing them to wear masks, which could further diminish their learning, we should end the mandates and let them get back to normal.
Stop Press: For a rigorous and comprehensive review of the evidence on mask efficacy, see this piece in City Journal by Jeffrey H. Anderson, a former Director of the Bureau of Justice Statistics.