Contact patterns before and during the UK's Autumn 2020 COVID-19 lockdown among university students and staff

Trickey, A.; Nixon, E. J.; Christensen, H.; Finn, A.; Thomas, A. C.; Relton, C.; Montgomery, C.; Hemani, G.; Metz, J.; Walker, J. G.; Turner, K.; Kwiatkowska, R.; Sauchelli, S.; Danon, L.; Brooks-Pollock, E.

Introduction Contact patterns are an important determinant of infection transmission. CONQUEST (COroNavirus QUESTionnaire) is an online survey of contacts for University of Bristol (UoB) staff and students. Results from 23/06/2020-24/11/2020 are used to investigate contact patterns among staff/students throughout various UK COVID-19 guidance periods. Methods Responses captured self-reported contacts on the previous day, with COVID-19 guidance periods split: post-first lockdown (23/06/2020-03/07/2020), relaxed guidance period (04/07/2020-13/09/2020), "rule-of-six" period (14/09/2020-04/11/2020), and the second lockdown (05/11/2020-25/11/2020). Results 722 staff (4199 responses) (mean household size: 2.6) and 738 students (1906 responses) (mean household size: 4.5) were included in the study. For staff, median contacts on the previous day were higher in the relaxed guidance and "rule-of-six" periods (3) than the post-lockdown and second lockdown periods (2). Mean contacts were higher during these two middle periods (4-6 per week) than the post-lockdown and second lockdown periods (~3). Mean contacts dropped between the last two periods (5.4 to 3.3), driven by a mean reduction in contacts in non-home/university locations (2.9 to 1.2). Few students responded until October. After 05/10/2020, the median was 2 and the mean was around 6-7 each week, until the second lockdown when it dropped to ~4. Mean number of contacts dropped between the last two periods (6.3 to 4.0) driven by a reduction in all contact types, including UoB contacts (3.5 to 2.5). Discussion The mean and median number of contacts for UoB staff and students were low compared to pre-COVID-19 studies throughout the survey period and lowest during the second lockdown.