Transmission of SARS-CoV-2 by children: a rapid review, 30 December 2019 to 10 August 2020

Background: The role of children in the transmission of SARS-CoV-2 during the early pandemic was unclear. Aim: We aimed to review studies on the transmission of SARS-CoV-2 by children during the early pandemic. Methods: We searched MEDLINE, Embase, the Cochrane Library, Europe PubMed Central and the preprint servers medRxiv and bioRxiv from 30 December 2019 to io August 2020. We assessed the quality of included studies using a series of questions adapted from related tools. We provide a narrative synthesis of the results. Results: We identified 28 studies from 17 countries. Ten of 19 studies on household and close contact transmission reported low rates of child-to-adult or child-to-child transmission. Six studies investigated transmission of SARS-CoV-2 in educational settings, with three studies reporting 183 cases from 14,003 close contacts who may have contracted COVID-19 from children index cases at their schools. Three mathematical modelling studies estimated that children were less likely to infect others than adults. All studies were of low to moderate quality. Conclusions: During the early pandemic, it appeared that children were not substantially contributing to household transmission of SARS-CoV-2. School-based studies indicated that transmission rates in this setting were low. Large-scale studies of transmission chains using data collected from contact tracing and serological studies detecting past evidence of infection would be needed to verify our findings.