College students wearing masks walking on campus

Study: Colleges can prevent 96% of COVID-19 infections with masks, distancing, and routine testing

The combination of three COVID-prevention strategies on college campuses—mask-wearing, social distancing, and routine testing—is up to 96% effective in preventing coronavirus infections, according to a new study co-authored by researchers from Case Western Reserve University with partners at Brigham and Women’s and Massachusetts General Hospitals, both affiliates of Harvard Medical School.

The research, published in Annals of Internal Medicine, has immediate significance as college semesters are starting again.

The study found that a combination of just two common measures—extensive social distancing implemented by college administrations and mandatory masks—would prevent 87% of campus COVID-19 infections and cost only $170 per infection prevented.

Adding routine lab-based testing to the mix would prevent 92% to 96% of COVID infections. But these additional reductions would come at a higher cost per infection prevented—$2,000 to $17,000 per infection prevented, depending on test frequency.

Pooyan Kazemian

As the infection rate continues to rise during the winter, the findings are especially meaningful for institutions of higher learning aiming to strike a balance between in-person and remote instruction, while managing costs to promote safety and reduce transmissions.

“Our analysis provides measurable metrics by which the value of social distancing, mask-wearing policies, and testing can be assessed. These data can help individual colleges make decisions regarding mitigation strategies tailored to their budgets, which may have already become strained because of the pandemic,” said Pooyan Kazemian, co-senior author of the study and an assistant professor of operations at Weatherhead School of Management at Case Western Reserve.

“It is clear that two common non-medical strategies are very effective and inexpensive—and allow for some in-person instruction,” said Kazemian. “While it’s true routine testing of the asymptomatic helps catch some infections early and reduce transmissions, they also pose the highest financial and operational burden, even if performed every 14 days.”

The study

Researchers examined 24 combinations of four common preventive strategies—social distancing, mask-wearing, testing and isolation—and calculated their effectiveness and cost per infection prevented.

The team took into account interactions between three groups: students, faculty, and the surrounding community (including staff), and used a computer simulation model—known as Clinical and Economic Analysis of COVID-19 interventions, or CEACOV—that simulated a semester of a mid-sized college of 5,000 students and 1,000 faculty.

“While states have started offering COVID-19 vaccine to health care workers, first responders, and long-term care facilities, it is unlikely that most students and university faculty and staff will be offered a vaccine until late in the spring semester,” said Kenneth A. Freedberg, co-senior author of the study and a professor of medicine at Harvard Medical School.

“Therefore, commitment to mask-wearing and extensive social distancing, including canceling large gatherings and reducing class sizes with a hybrid education system, remains the primary strategy for minimizing infections and keeping the campus open during the spring semester,” Freedberg added.

The authors also modeled online-only education with a campus being closed and found it less effective in preventing infections than keeping the campus open and using masks and distancing.

“While closing the campus and switching to online-only education would reduce infections by 63% among students, it would be less effective than opening the campus and implementing a mask-wearing and social distancing policy, which would reduce infections by 87% among students,” said Elena Losina, lead author of the study and director of the Policy and Innovation eValuation in Orthopedic Treatments (PIVOT) Center at the Brigham and Women’s Hospital and Robert W. Lovett professor of orthopedic surgery at Harvard Medical School. “When a campus is closed, there are still infections among students who return to live off-campus.

“Our analysis provides measurable metrics by which the value of social distancing, masks policy and testing could be assessed. These data could help individual colleges make decisions regarding mitigation strategies tailored to their budgets,”  Losina added.

For more information, contact Daniel Robison at

This article was originally published Jan. 13, 2021.