To the editor:

Usually, I am happy when my experiments work. If they do, it affirms my initial assumptions and supports the story that I constructed around the available data. This is called hypothesis testing. But with Covid-19, I’m not sure I need to test the idea that masks prevent transmission, and I’m not sure I need to test my concepts of common sense. Many students, faculty and staff dispersed from campus for spring break, then returned, bringing back as a souvenir new contacts from around the world.

Indeed, we tested but we didn’t mask, and so we were able to tell if the masks were effective. The CDC tells us that, on average, symptoms of the infected will appear within five to seven days. That means if exposed to a newly infected person within seven days after break, there would be positive test results for two weeks after returning. That is exactly what we saw on campus for several weeks after break, evidenced by a rising infection rate. This rise is completely correlated with removal of masks in buildings. While this is only a correlation, it supports the hypothesis that masks prevent transmission.

So then why did we need to do this experiment? Because we are understandably so eager to return to normal. The choice to remove masks was indeed a choice, and it is wonderful to see smiling faces and expressions that transmit intentions and wishes and emotions, understanding and misunderstanding.

Some correctly worry about the immunocompromised and those with underlying health conditions, or live with very young or very old family members, but we should also worry about the disruption to the classroom. As students test positive, they are now missing class and important end-of-the-semester work. Indeed students and faculty alike saw a significant disruption to academic work. And so the masks went back on.

Once again the rates of infection have dropped. If we continue to mask for the remainder of the semester, we will have more assurance that students can complete their semester and faculty can be there to teach. But, no, the rates have dropped again so we take off the masks, again, and the cycle repeats itself.  For now, I know I’ll keep wearing my mask inside all buildings and that way I can keep teaching my courses, whether there are any students attending or not. Of course, that is if I can continue to teach…

Sincerely,

Bruce Kohorn, Linnean Professor of Biology and Biochemistry