Pediatric household transmission of SARS-CoV-2 infection

Abstract

BACKGROUND: As a result of low numbers of pediatric cases early in the COVID-19 pandemic, pediatric household transmission of SARS-CoV-2 remains an understudied topic. This study sought to determine whether there are differences in the odds of household transmission for younger children compared to older children. METHODS: We assembled a cohort of all individuals in Ontario, Canada with laboratory-confirmed SARS-CoV-2 infection between June 1 and December 31, 2020. The cohort was restricted to individuals residing in private households (N=132,232 cases in 89,191 households), identified through an address matching algorithm. Analysis focused on households in which the index case was aged <18 years. Logistic regression models were fit to estimate the association between age group of pediatric index cases (0-3, 4-8, 9-13, and 14-17 years) and odds of household transmission. RESULTS: A total of 6,280 households had pediatric index cases, and 1,717 (27.3%) experienced secondary transmission. Children aged 0-3 years had the highest odds of household transmission compared to children aged 14-17 years (model adjusted for gender, month of disease onset, testing delay, and average family size: 1.43, 95% CI: 1.17-1.75). This association was similarly observed in sensitivity analyses defining secondary cases as 2-14 days or 4-14 days after the index case, and stratified analyses by presence of symptoms, association with a school/childcare outbreak, or school/childcare reopening. Children aged 4-8 years and 9-13 years also had increased odds of transmission (4-8: 1.40, 95% CI: 1.18-1.67; 9-13: 1.13, 95% CI: 0.97-1.32). CONCLUSIONS: This study suggests that younger children are more likely to transmit SARS-CoV-2 infection compared to older children, and the highest odds of transmission was observed for children aged 0-3 years. Differential infectivity of pediatric age groups has implications for infection prevention controls within households, as well as schools/childcare, to minimize risk of household secondary transmission.

SARS-CoV-2 Omicron sublineage BA.2 replaces BA.1.1: genomic surveillance in Japan from September 2021 to March 2022

“…However, our data are derived from random sampling, therefore these results are expected to better reflect real-world conditions. Although a high incidence of household COVID-19 infections stemming from young children has been reported [35], our results indicate that the Omicron strain retains a fairly high viral load across age groups, which may contribute to the high infectivity of the Omicron strain and its accelerated spread. These data provide insights for determining appropriate COVID-19 prevention and control measures for homes, schools, workplaces, and facilities for the elderly during the spread of Omicron strain viruses.…”

SARS-CoV-2 Transmission Dynamics in Households With Children, Los Angeles, California

“…By following our patients over the pandemic, we found that both adults and children are responsible for bringing SARS-CoV-2 to the household as the index case. A recent population-based cohort study in Canada also found that younger children were more likely to transmit SARS-CoV-2 infection compared with older children ( 36 ). During the period with lower case numbers in the community ( 23 ), we observed that the index cases were most frequently children, despite public school closures.…”

Population age and household structures shape transmission dynamics of emerging infectious diseases: a longitudinal microsimulation approach

“…Children tend to be more susceptible to infections given that their immune system is still maturing, while in older adults, the ageing of the immune system (immunosenescence) may increase their susceptibility to infection and to more severe disease upon infection [4]. Likewise, the infectiousness of infected individuals may also vary by age [5,6].…”