The COVID-19 Schools Infection Survey in England: Protocol and participation profile for a prospective, observational cohort study (Preprint)

BACKGROUND One of the most debated questions in the COVID-19 pandemic has been the role of schools in SARS-CoV-2 transmission. The COVID-19 Schools Infection Survey (SIS) aims to provide much-needed evidence addressing this. OBJECTIVE This paper presents the study protocol and participation profile for the SIS study, aimed at assessing the role of schools in SARS-CoV-2 infection and transmission within school settings, and investigating how transmission within and from schools could be mitigated through implementation of school COVID-19 control measures. METHODS SIS was a multisite, prospective, observational cohort study conducted in a stratified random sample of primary and secondary schools in selected local authorities in England. Six bio-behavioural surveys were planned among participating students and staff during the 2020/21 academic year, between November 2020 and July 2021. Key measurements were SARS-CoV-2 virus prevalence, assessed by nasal swab polymerase chain reaction; anti-SARS-CoV-2 (nucleocapsid protein) antibody prevalence and conversion, assessed in finger-prick-blood for staff and oral-fluid for students; student and staff school attendance rates; feasibility and acceptability of school-level implementation of SARS-CoV-2 control measures; and investigation of selected school outbreaks. The study received approvals from the UK Health Security Agency Research Support and Governance Office (NR0237) and London School of Hygiene & Tropical Medicine Ethics Review Committee (ref:22657). RESULTS Data collection and laboratory analyses were completed by September 2021. A total of 22,585 individuals: 1,891 staff and 4,654 students from 59 primary schools and 5,852 staff and 10,188 students from 97 secondary schools participated in at least one survey. On average, across survey rounds, staff and student participation rates were 45.2% and 16.4% respectively in primary schools and 30.0% and 15.2% in secondary schools. While primary student participation increased over time, and secondary student participation remained reasonably consistent, staff participation declined across rounds, especially for secondary school staff (41.7% in Round 1 and 22.1% in Round 6). While staff participation overall was generally reflective of the eligible staff population, student participation was higher in schools with low absenteeism, a lower proportion of students eligible for free school meals and from schools in the least deprived locations (in primary schools 9.6% participants were from schools in the least deprived quintile compared with 5.7% of eligible students). CONCLUSIONS We outline the study design, methods and participation, and reflect on the strengths of the SIS study as well as the practical challenges encountered, and the strategies implemented to address these challenges. The SIS study, by measuring current and incident infection over time, alongside the implementation of control measures in schools, across a range of settings in England, aims to inform national guidance and public health policy for educational settings. CLINICALTRIAL