SARS-CoV-2 circulation in the school setting: A systematic review and meta-analysis

ABSTRACT Background The contribution of children to viral spread in schools is still under debate. We conducted a systematic review and meta-analysis of studies to investigate SARS-CoV-2 transmission in the school setting. Methods Literature searches from April, 2021 and repeated on May, 15 th 2021 yielded a total of 1088 publications: screening, contact tracing and seroprevalence studies. MOOSE guidelines were followed and data analyzed using random-effects models. Results From screening studies involving more than 120,000 subjects, we estimated 0.31% (95% Confidence Interval [CI] 0.05-0.81%) SARS-CoV-2 point prevalence in schools. Contact tracing studies, involving a total of 112,622 contacts of children and adults, showed that onward viral transmission was limited (2.54%; 95%CI 0.76-5.31). Young index cases were found to be 74% significantly less likely than adults to favor viral spread (Odds Ratio [OR]=0.26; 95%CI 0.11-0.63) and were less susceptible to infection (OR=0.60; 95% CI 0.25-1.47). Finally, from seroprevalence studies, with a total of 17,879 subjects involved, we estimated that children are 43% significantly less likely than adults to test positive for antibodies (OR=0.57; 95%CI: 0.49-0.68). In conclusion, testing all subjects in schools, independently of symptoms, students less likely than adults favor viral spread and SARS-CoV-2 circulation in schools was found to be limited. KEY POINTS Question What is the infectivity and susceptibility of students and staff exposed to SARS-CoV-2 in the school setting? Findings This systematic review and meta-analysis of all available data shows that SARS-CoV-2 viral spread is limited and child-to-adult transmission in the school setting scarce. Summary estimates indicate that young index cases were 74% significantly less likely than adults to favor viral spread and children are 43% less susceptible than adults. Meaning Overall, SARS-CoV-2 circulation in schools was limited and could be reasonably controlled with appropriate mitigation measures.