Calculating COVID-19 risk

A new COVID-19 risk calculator developed at Harvard T.H. Chan School of Public Health can help people understand the ways that masking, ventilation, filtration, and other factors can mitigate the spread of COVID-19 in indoor environments.

The tool, developed by Joseph Allen, associate professor of exposure assessment science, and his team at the Healthy Buildings program, is based on a model of the COVID-19 outbreak on the Diamond Princess cruise ship in early 2020 as well as other superspreader events.

Allen and Parham Azimi, a research fellow in the exposure, epidemiology and risk program at Harvard Chan School, described how to use the calculator in an April 6, 2021, opinion piece in the Washington Post.

Users can plug in information such as the size of the room they’ll be in, how long they’ll be in the room, whether they’ll be seated or active, whether people are wearing masks and staying six feet apart from each other, and whether the windows are open. Once all the information is filled in, the tool produces a risk estimate. The tool also enables users to switch parameters in order to see how beefing up safety measures can reduce risk.

Read the Washington Post article: Opinion: So you’re unvaccinated and want to see a friend. Here’s how to calculate your risk.