Masking worked, along with fewer exposure encounters, to help limit the incidence of COVID-19 infection among largely unvaccinated university students in Missouri, researchers found.
Among nearly 400 close contacts of students who tested positive for SARS-CoV-2, the likelihood of a positive test result was more than five times higher in situations where at least one of the two individuals was unmasked versus situations where both were masked (adjusted odds ratio [aOR] 5.4, 95% CI 1.5-36.5, P=0.008), reported Terri Rebmann, PhD, RN, of St. Louis University in Missouri, and colleagues.
Notably, multivariate analyses found that any additional exposure was linked with a 40% increase in the chances of contracting SARS-CoV-2 (aOR 1.4, 95% CI 1.2-1.6), the authors wrote in the Morbidity and Mortality Weekly Report.
“These findings reinforce that universal masking and having fewer encounters in close contact with persons with COVID-19 prevents the spread of SARS-CoV-2 in a university setting,” Rebmann and coauthors noted. “Universities opening for in-person instruction could consider taking mask use into account when determining which unvaccinated close contacts require quarantine if enforced testing protocols are in place.”