[Symptoms of SARS-CoV-2 infections in children of day care age].

Background: The symptoms of SARS-CoV‑2 infections in children are mostly mild; however, the symptoms are highly variable. There are only a few studies on non-hospitalized children. The clinical picture described in hospitalized children cannot be transferred to non-hospitalized children and the frequency of certain symptoms in children may thus be overestimated. Furthermore, most studies include a broad age group (up to 18 years). The symptoms of younger children have so far been described in less detail. Objective: The paper aims to describe the frequency of COVID-19 symptoms in younger children (1-6 years old). Data of the two modules COALA ( Material and methods: The COALA study investigated 30 SARS-CoV‑2 outbreaks in day care centers where at least 1 SARS-CoV‑2 case was reported between October 2020 and June 2021. Using a prospective study design, day care children who were infected with SARS-CoV‑2 and their contact persons were studied over a period of 12 days (including regular SARS-CoV‑2 testing, retrospective interviews and daily symptom reporting). The results from the COALA study were compared with data from COVID-19 surveillance cases (CATS) for the same age group and time period. In Germany, SARS-CoV‑2 cases are reported to the local health authorities by physicians and laboratories. When reporting cases symptoms can be reported as well. Results: From the COALA study, interview and reported symptom data were available for 289 children from the participating day care centers. Of 39 children with a SARS-CoV‑2 infection (wild-type, α‑variant), 64% had at least 1 symptom; of the children who tested negative for SARS-CoV‑2, 40% had at least 1 symptom. In both groups, rhinitis was the most common symptom (36% vs. 25%, n. s.). From the surveillance data (CATS), clinical information was available for 84,371 SARS-CoV‑2 positive children; fever was most common (27%) along with rhinitis (26%). Severe symptoms such as dyspnea were rarely reported in the outbreak investigations and in the surveillance data (3% and 1%, respectively). Conclusion: Day care-aged children infected with SARS-CoV‑2 usually have mild or asymptomatic courses. Their symptoms are similar to those of children who tested negative for SARS-CoV‑2 from the same day care centers; thus, the observed COVID-19 symptoms are nonspecific. Combining data from the two modules is useful: findings from a very large database, as provided by the surveillance data, are complemented by findings from day care center outbreaks, where detailed prospective data on infected children can be compared with those of children who tested negative for SARS-CoV‑2.