Roles of children, isolation measures and socioeconomic status in SARS-CoV-2 household transmission: a retrospective cohort study in a southern US city

Objective: There has been significant debate about both the role of children in SARS-CoV-2 community transmission as well as the potential harm or lack thereof of the virus in the paediatric population. We aimed to better understand how children are impacted by a SARS-CoV-2 household infection and to identify behavioural and social factors related to infection. Methods: A cross-sectional study was conducted on households with children and a recent SARS-CoV-2 infection in Atlanta, GA. Participants were enrolled from December 2020 through November 2021. Salivary IgG against SARS-CoV-2 spike and nucleocapsid antigens was measured and household and infection data collected and analysed. Results: 49 households participated, including 121 adults and 57 children with 118 (66%) individuals having been infected with SARS-CoV-2. Mean SARS-CoV-2 secondary infection rate was 0.55 (95% CI 0.41 to 0.69) and median, 0.67 (range 0-1.0). Incidence rate did not differ significantly between households with paediatric versus adult index cases (incidence rate ratio (IRR) 0.97, 95% CI 0.63 to 1.49). However, sharing a bedroom or bathroom was associated with a higher incidence of secondary infection (IRR 2.36, 95% CI 1.49 to 3.74). Neighbourhood deprivation index was associated with higher household SARS-CoV-2 incidence, but this did not reach statistical significance. Conclusions: Child index cases appeared as likely to result in household secondary SARS-CoV-2 infections as adult index cases, while sharing rooms was associated with higher incidence of infection. This study highlights the importance of isolation measures to prevent household transmission of SARS-CoV-2 as well as counters common thought that children are less likely to transmit infection.