SARS-CoV-2 incidence, transmission, and containment measures in daycare centers during the COVID-19 pandemic-findings from the Corona Daycare Study

Background Daycare centers are of substantial sociopolitical and pedagogical relevance; at the same time, the close contact of children in daycare groups among each other and with employees favors the transmission of infections. In the COVID-19 pandemic, questions arose about how infection events occur in daycare centers, what role daycare children play in the pandemic, and what protective and hygienic measures are implemented in daycare centers. From 06/2020 to 12/2021, we conducted the "Corona Day Care Study," in which we address pedagogical and infection epidemiological topics in a joint approach. Methods In the study, data are collected from different sources. Official reporting data as well as weekly data from daycare centers in the so-called KiTa Register are continuously evaluated. In addition, SARS-CoV-2 outbreaks in daycare centers are investigated on site by repeated sample collection and interviews. Results SARS-CoV-2 infection incidence in daycare centers or in daycare-aged children was very dynamic from 03/2020 to 05/2021. In the second and third pandemic waves, the number of SARS-CoV-2 outbreaks in daycare centers rose sharply, accompanied by a substantial increase in daycare and group closures. Most recently, the proportion of affected children in outbreaks increased steadily. However, preliminary examinations of SARS-CoV-2 outbreaks (n = 28) revealed that, on average, only a fraction of daycare contact persons (6.8%) were infected by child index cases. Transmission frequencies differed markedly between the individual daycare centers. Discussion The combination of regularly collected reporting and survey data as well as outbreak investigations allows a multilayered monitoring and understanding of infection events in daycare centers; its findings could be incorporated into recommendations for public health measures.