Transmission of SARS-CoV-2 by Children and Young People in Households and Schools: A Meta-Analysis of Population-Based and Contact-Tracing Studies

Background: The role of children and young people (CYP) in transmission of SARS-CoV-2 in household and educational settings remains unclear. We undertook a systematic review and meta-analysis of contact-tracing and population-based studies at low risk of bias. Methods: We searched 4 electronic databases on 5 April for contact-tracing studies and population-based studies informative about transmission of SARS-CoV-2 from 0-19 year olds in household or educational settings. We excluded studies at high risk of bias, including from under-ascertainment of asymptomatic infections. We undertook multilevel random effects meta-analyses of secondary attack rates (SAR: contact-tracing studies) and school infection prevalence, and used meta-regression to examine the impact of community SARS-CoV-2 incidence, mitigations and attendance on school infection prevalence. Findings: 4179 abstracts were reviewed, resulting in 37 included studies (17 contact-tracing; 18 population studies; 2 mixed studies). The pooled relative transmissibility of CYP compared with adults was 1.00 (0.73, 1.37) in adjusted household studies. The pooled SAR from 0CYP was significantly lower in school studies (0.5% (0.1, 1.6) than household studies (7.3% (2.5, 21.8) - p<0.0001. There was no difference in SAR from CYP to child or adult contacts. School population studies showed little evidence of clustering in classes within schools. School infection prevalence was associated with contemporary community 14-day incidence (OR 1.003 (1.001, 1.004), p