Roles of Children and Adolescents in COVID-19 Transmission in the Community: A Retrospective Analysis of Nationwide Data in Japan

Abstract

Background: Roles of children and adolescents in spreading coronavirus disease 2019 (COVID-19) in the community is not fully understood.Methods: We analyzed the data of 7,758 children and adolescents with COVID-19 and characteristics of secondary transmission generated by these cases using case information published by local governments. Ratio of pediatric and adolescent cases generating secondary transmission was calculated for various social settings.Results: The incidence of COVID-19 was 24.8 cases per 105 population aged between 0 and 9 years, and 59.2 among those aged between 10 and 19 years, which was lower than that among individuals of all age groups (79.6 per 105 population) between January 15 and October 31, 2020. The proportion of cases generating secondary cases was 8.3% among infants and young children in nursery schools and kindergartens, 16% among children and adolescents attending primary schools, 34% among those attending junior high schools, 43% among those attending high schools, 31% among those attending professional training colleges, and 24% in those attending universities. Households were the most common setting for secondary transmission.Conclusion: The risk of generating secondary cases might be limited among pediatric and adolescent cases with COVID-19, especially in settings outside households. Effectiveness of traditional mitigation measures (e.g., school closures) to suppress COVID-19 transmissions should be carefully evaluated.

The Impact of the COVID-19 Pandemic on the General Public in Urban and Rural Areas in Southern Japan

“…In addition, respondents who had a child under 12 years old were shown to be associated with higher levels of difficulty and anxiety. This result is evident, as school closure for months can increase childcare needs massively [61], and possibly because kids were deemed to play a major role in spreading the virus during the first wave of COVID-19 according to what we have learnt from influenza [62]. Our results also indicated a significant difference between urban and rural respondents regarding the difficulty content related to school closure.…”

Household Secondary Transmission of the Severe Acute Respiratory Syndrome Coronavirus 2 Alpha Variant From a Community Cluster in a Nursery in Japan

“…Household transmission, especially from parents, is one of the most common routes by which children are infected with SARS-CoV-2. 5 Because infected parents may transmit SARS-CoV-2 to their children, secondary transmission in the household is important. However, it is difficult to keep physical distance from and avoid close contact with family members and to wear masks during conversation or meals at home, where space is often limited.…”

“…[1][2][3][4] Children are usually infected with SARS-CoV-2 at home in households, rather than in the community. 5 The spread of SARS-CoV-2 in nurseries and schools, which leads to cluster formation of COVID-19 among children, had been uncommon. When clusters did occur, they began in adults rather than in children.…”

Surveillance of Close Contacts and Implications of Pediatric Patients with COVID-19–Experiences from a Single Residential Treatment Center

“… 8 The risk of SARS-CoV-2 transmission among children and adolescents is likely to be low, 9 and children and adolescents would play a less significant role in the transmission of SARS-CoV-2 at a population level, compared to the 2009 H1N1 pandemic. 10 However, children still infect others without social distancing or other quarantine rules. The secondary attack rates of variant strains estimated from contact tracing data appear to be higher than those of the wild type, but the relative difference between the young and adults seems to be preserved.…”