Social risk factors for SARS-CoV-2 acquisition in University students: cross sectional survey

Objectives

To define risk factors for SARS-CoV-2 infection in University of Cambridge students during a period of increased incidence in October and November 2020.

Study design

Survey

Methods

Routine public health surveillance identified a marked increase in the numbers of University of Cambridge students with respiratory illness and SARS-CoV-2 positivity in the 10 days after a national lockdown was announced in the UK on 5 November 2020. Cases were identified both through symptom-triggered testing and a universal asymptomatic testing program. An online questionnaire was sent to all University of Cambridge students on 25 November to investigate risk factors for testing positive in the period after 30 ^th October 2020. This asked about symptoms, SARS-CoV-2 test results, in-person teaching settings, other aspects of University life, and attendance at social events in the period just prior to lockdown, from 30 ^th October and 4 ^th November 2020. Univariate and multivariable analyses were undertaken evaluating potential risk factors for SARS-CoV-2 positivity.

Results

Among 3,980 students responding to the questionnaire, 99 (2.5%) reported testing SARS-CoV-2 positive in the period studied; 28 (28%) were asymptomatic. We found strong independent associations with SARS-CoV-2 positivity were attendance at two social settings in the City of Cambridge (adjusted odds ratio favouring disease 13.0 (95% CI 6.2,26.9) and 14.2 (95% CI 2.9,70)), with weaker evidence of association with three further social settings. By contrast, we did not observe strong independent associations between disease risk and type of accommodation or attendance at, or participation in, a range of activities associated with the University curriculum.

Conclusions

Attendance at social settings can facilitate widespread SARS-CoV-2 transmission in University students. Constraint of transmission in higher education settings needs to emphasise risks outside University premises, as well as a COVID-safe environment within University premises.

Highlights

• In a population of University students, a large increase in individuals testing positive for SARS-CoV-2 occurred in the days following a national lockdown.

• Attendance at particular social gatherings was strongly linked to the development of disease, independent of other risk factors.

• By contrast, a range of risk factors including age, gender, ethnicity, accommodation type, shared kitchen facilities, attendance at supermarkets, and attending teaching sessions were not significantly associated with SARS-CoV-2 risk.

• These data emphasise the increased risk associated with University students attending social settings with large numbers of others, even when other risks associated with university attendance are well controlled.