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ObjectiveTo quantify the number of undetected SARS-CoV-2 infections in educational settings.DesignSerial SARS-CoV-2 seroprevalence study before and during the second wave of the COVID-19 pandemic.SettingSecondary school in Dresden, Germany.ParticipantsGrade 8–12 students and their teachers were invited to participate in serial blood sampling and SARS-CoV-2 IgG antibody assessment.Main outcome measureSeroprevalence of SARS-CoV-2 antibodies in study population.Results247 students and 55 teachers participated in the initial study visit and 197 students and 40 teachers completed follow-up. Seroprevalence increased from 1.7% (0.3–3.3) to 6.8% (3.8–10.1) during the study period mirroring the increase of officially reported SARS-CoV-2 infections during this time. The ratio of undetected to detected SARS-CoV-2 infections ranged from 0.25 to 0.33.ConclusionsWe could not find evidence of relevant silent, asymptomatic spread of SARS-CoV-2 in schools neither in a low prevalence setting nor during the second wave of the pandemic, making it unlikely that educational settings play a crucial role in driving the SARS-CoV-2 pandemic.Trial registration numberDRKS00022455.

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Comparing seroprevalence and antibody kinetics in three different commercially available assays for SARS-CoV-2. Serostatus of COVID-19 patients was analyzed 5 months and 10 months after their infection, using three different assays: Diasorin LIAISON, Euroimmun, Abbott Diagnostics ARCHITECT. Seropositivity at baseline differed significantly depending on the assay (Diasorin 81%, Euroimmun 83%, Abbott 59%). At follow-up antibody levels detected in the Diasorin assay were stable, while there was a significant loss in seropositivity in the Euroimmun and Abbott assays. There are significant differences in SARS-CoV-2 antibody kinetics based on the specific assay used.

Purpose Comparing seroprevalence and antibody kinetics in three different commercially available assays for SARS-CoV-2. Methods Serostatus of COVID-19 patients was analyzed 5 months and 10 months after their infection, using three different assays: Diasorin LIAISON, Euroimmun, Abbott Diagnostics ARCHITECT. Results Seropositivity at baseline differed significantly depending on the assay (Diasorin 81%, Euroimmun 83%, Abbott 59%). At follow-up antibody levels detected in the Diasorin assay were stable, while there was a significant loss in seropositivity in the Euroimmun and Abbott assays. Conclusion There are significant differences in SARS-CoV-2 antibody kinetics based on the specific assay used.

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Purpose To quantify the number of SARS-CoV-2 infections in students and teachers in 14 Secondary schools in eastern Saxony, Germany. Seroprevalence of SARS-CoV-2 antibodies in study population. Number of undetected cases. Methods Serial seroprevalence study. Results The role of educational settings in the SARS-CoV-2 Pandemic is still controversial. Seroprevalence increases from 0.8 to 5.9% from October to December when schools remained open and to 12.2% in March/April during a strict lockdown with closed schools. The ratio of undetected to detected cases decreased from 0.76 to 0.44 during the study period. Conclusion During the second and third wave of the pandemic in Germany, students and teachers are not overrepresented in SARS-CoV-2 infections. The percentage of undetected cases is moderate and decreases over time. The risk of contracting SARS-CoV-2 within the household is higher than contracting it in educational settings making school closures rather ineffective in terms of pandemic control measures or individual risk reduction in children and adolescents. Trial registration DRKS00022455 (July 23rd, 2020).

Objectives Previous data indicate that children might play a less crucial role in SARS-CoV-2 transmission than initially assumed. We conducted a study to gain further knowledge on prevalence, transmission and spread of SARS-CoV-2 among preschool children, their parents and caretakers. Study design Children, their parents and care givers in 14 childcare facilities in Dresden, Saxony/ Germany were invited to participate in the KiTaCoviDD19-study between July 2020 and January 2021. Seroprevalence of SARS-CoV-2 antibodies was assessed up to 4 times during the study period in all participating adults and personal characteristics as well as epidemiological information of personal SARS-CoV-2 history were obtained. Stool viral shedding of SARS-CoV-2 was analyzed every 2-4 weeks in all participating children. Results 318 children, 299 parents and 233 childcare workers were enrolled. By January 2021 11% of the participating adults were detected seropositive, whereas the rate of SARS-CoV-2 positive children was 6.8%. Overall, we detected 17 children with SARS-Cov-2 viral shedding in 8 different childcare facilities. In 4 institutions there occurred a maximum of three connected cases in children. About 50% of SARS-CoV-2 infections in children could not be connected to a secondary case within our study population. Conclusion This study could not provide evidence for a relevant asymptomatic (silent) spread of SARS-CoV-2 in childcare facilities, neither in a low nor a high prevalence setting. This finding adds to the evidence that childcare and educational settings do not play a crucial role in driving the SARS-CoV-2 pandemic.