Abstract
Background: Spread of variants of concerns (VOCs) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an increase in children with coronavirus disease 2019 (COVID-19). In February 2021, clusters of the Alpha variant of SARS-CoV-2 started to be reported in Niigata, Japan, including a large nursery cluster. We investigated the transmission routes and household secondary attack rates (SARs) in this cluster.
Methods: Epidemiologic data related to a nursery cluster in Niigata, Japan, particularly child-origin and adult-origin SARs, were analyzed. VOCs were confirmed by whole-genome sequencing of virus from patients.
Results: In total, 42 persons (22 children and 20 adults) in the cluster were infected with the Alpha variant. In the nursery, 13 of 81 children (16.0%) and 4 of 24 teachers (16.7%) were infected. SARS-CoV-2 later spread to 25 persons (10 children and 15 adults) outside the nursery. Child-origin and adult-origin household SARs were 27.7% (13/47) and 47.0% (8/17) ( P = 0.11), respectively, which were higher than rates attributable to non-VOCs in previous studies.
Conclusions: As compared with non-VOCs, the Alpha variant of SARS-CoV-2 exhibited high transmissibility among children and adults and may pose a high risk for household secondary transmission from SARS-CoV-2-infected children. Increased transmissibility of current or future VOCs could lead to greater transmission from children to adults or other children.
【초록키워드】 COVID-19, coronavirus disease, whole-genome sequencing, SARS-CoV-2, Coronavirus disease 2019, coronavirus, VoC, children, SARS, variants of concern, Transmission, severe acute respiratory syndrome Coronavirus, virus, variants, secondary attack rate, Adults, Transmissibility, VOCs, Cluster, Japan, transmission route, Alpha variant, patients, Transmission routes, high risk, acute respiratory syndrome, acute respiratory syndrome coronavirus, Previous studies, acute respiratory syndrome coronavirus 2, secondary transmission, nursery, greater, analyzed, were infected, spread to, reported, investigated, exhibited, increase in, Increased, household SAR, 【제목키워드】 coronavirus 2, household, respiratory, secondary,