Regular testing key to reducing campus Covid spread – modelling

The return of students to Canadian campuses could lead to a doubling of Covid-19 cases in university towns, but regular testing would significantly reduce the number of infections, according to a study.

The paper found that more than two-thirds of infections attributable to the return of university students occur in the general population, not in the student population itself, leading to increased pandemic-related hospitalisations and deaths.

The modelling by Western University researchers, which is on the preprint repository medRxiv, was based on Covid-19 transmission and hospital resource use in London, Ontario – a representative mid-sized city with a relatively large post-secondary student population and a previously low level of Covid-19 activity.

The model identified the number of infections expected among the university student population, the general population and long-term care residents, before and after the return of university students on 1 September, and the populations’ response to increased cases, hospitalisations and Covid-19 mortality.

It found that in a scenario in which students immediately reduced their contact with other people by 24 per cent compared with pre-Covid levels, the total number of infections in the community would increase by 87 per cent following the return of students, with 71 per cent of the incremental infections occurring in the general population. This would cause social and economic restrictions to be re-engaged three weeks earlier and an incremental 17 Covid-19 deaths, according to the research.

Scenarios in which students have an initial short-term increase in contacts with other students before reducing socialising could increase infections in the community by 150 per cent or more, it adds.

In such instances, screening asymptomatic students every five days reduces the number of infections attributable to the introduction of university students by 42 per cent and delays the re-introduction of social and economic restrictions by a week. Testing every 14 days reduces the number of infections by 22 per cent.

However, even a one-time mass-screening event early in the term, thereby identifying and isolating a large fraction of asymptomatic infections in the student population, would interrupt transmission and reduce community spillover, according to the research. While one-time mass screening prevents fewer infections than regular testing, the paper says it is highly efficient in terms of infections prevented per screening test performed.

Authors Lauren Cipriano, Wael Haddara, Gregory Zaric and Eva Enns say it is the first study to evaluate the impact of high rates of Covid-19 transmission among university students on the community in which the university is located and the first to evaluate the benefits of a potentially more feasible one-time testing event following a surge in social activity on campus.

ellie.bothwell@timeshighereducation.com