Prospective Active National Surveillance of Preschools and Primary Schools for SARS-CoV-2 Infection and Transmission in England, June 2020: (sKIDs: COVID-19 Surveillance in School KIDs) (preprint)

ABSTRACT

Background: Many countries re-opened schools after national lockdown but little is known about the risk of SARS-CoV-2 infection and transmission in educational settings. Public Health England conducted six-month prospective surveillance in primary schools across England. Methods: The COVID-19 Surveillance in School KIDs (sKIDs) study included two arms weekly nasal swabs for ≥4 weeks following partial reopening during the summer half-term (June to mid-July 2020) and blood sampling with nasal and throat swabs at the beginning and end of the summer half-term, and, following full reopening in September 2020, at the end of the autumn term (end-November 2020). Results: In round 1, 12,026 participants (59.1% students, 40.9% staff) in 131 schools had 43,091 swabs taken. Weekly SARS-CoV-2 infection rates were 3.9 (1/25,537; 95% CI, 0.10-21.8) and 11.3 (2/17,554; 95% CI, 1.4-41.2) per 100,000 students and staff. At recruitment, N-antibody positivity in 45 schools was 11.1% (91/817; 95%CI, 9.2-13.5%) in students and 15.1% (209/1381; 95%CI, 13.3-17.1%) in staff, similar to local community seroprevalence. Seropositivity was not associated with school attendance during lockdown or staff contact with students. Round 2 participation was 73.7% (1,619/2,198) and only five (4 students, 1 staff) seroconverted. In round 3, when 61.9% (1,361/2,198) of round 1 participants were re-tested, seroconversion rates were 3.4% (19/562; 95%CI, 2.0-5.2) in students and 3.9% (36/930; 95%CI, 2.7-5.3) in staff. Conclusions: SARS-CoV-2 infection rates, assessed using nasal swabs for acute infection and serum antibodies for prior infection, were low following partial and full reopening of primary schools in England.Funding Statement This surveillance was funded by the Department of Health and Social Care (DHSC).Declaration of Interests None to declare.Ethics Approval Statement The surveillance protocol was approved by the Public Health England Research Ethics Governance Group (R&D REGG Ref NR0209, 16 May 2020).