NOTE: This article was originally posted on June 28, but has since been substantially modified as I realized the initial analysis underestimated personal risk substantially. This version provides more information on the risk calculation approach taken — please treat with caution though, and let me know if you come across anything that doesn’t look right!
If you’re a student or instructor facing the prospect of in-person classes in the fall, and worrying about what the risks are of being infected by COVID19 as a result, you’re not alone.
Like many, I’ve been grappling with the potential risks of in-person teaching in the light of COVID119, and wondering just how effective measures being discussed are going to be.
Most universities are working hard to reduce the risks through measures like temperature screening, mask-usage, reduced occupancy and hybrid in-person/online teaching models. Yet without a clear sense of where these measures are backed up by evidence, I find myself finding it hard to get a good feel for what the personal risks might be.
And that’s speaking as a person who studies risk for a living!
Paying attention to ventilation in classrooms
One factor in particular that has been bothering me, coming in part from many years studying and leading research on aerosol exposure, is the rate at which potentially contaminated air in enclosed spaces is replaced with clean air, and how this in turn impacts potential risk. And as a result, I’ve been pleased to see a growing body of preliminary research looking at just this — including a recent pre-print on medRxiv from Dr.Shelly Miller at the University of Colorado, Boulder, and her colleagues, on COVID19 transmission associated with the Skagit Valley Chorale superspreading event.
