The role of children in transmission of SARS-CoV-2 variants of concern within households: an updated systematic review and meta-analysis, as at 30 June 2022

BACKGROUND: Meta-analyses and single-site studies have established that children are less infectious than adults within a household when positive for ancestral SARS-CoV-2. In addition, children appear less susceptible to infection when exposed to ancestral SARS-CoV-2 within a household. The emergence of SARS-CoV-2 variants of concern (VOC) has been associated with an increased number of paediatric infections worldwide. However, the role of children in the household transmission of VOC, relative to the ancestral virus, remains unclear. AIM: We aimed to evaluate children's role in household transmission of SARS-CoV-2 VOC. METHODS: We perform a meta-analysis of the role of children in household transmission of both ancestral SARS-CoV-2 and SARS-CoV-2 VOC. RESULTS: Unlike with the ancestral virus, children infected with VOC spread SARS-CoV-2 to an equivalent number of household contacts as infected adults and were equally as likely to acquire SARS-CoV-2 VOC from an infected family member. Interestingly, the same was observed when unvaccinated children exposed to VOC were compared with unvaccinated adults exposed to VOC. CONCLUSIONS: These data suggest that the emergence of VOC was associated with a fundamental shift in the epidemiology of SARS-CoV-2. It is unlikely that this is solely the result of age-dependent differences in vaccination during the VOC period and may instead reflect virus evolution over the course of the pandemic.