SARS-CoV-2 seroprevalence in students and teachers: a longitudinal study from May to October 2020 in German secondary schools.

OBJECTIVE

To quantify the number of SARS-CoV-2 infections in secondary schools after their reopening in May 2020.

DESIGN

Repeated SARS-CoV-2 seroprevalence study after the reopening of schools and 4 months later.

SETTING

Secondary school in Dresden, Germany.

PARTICIPANTS

1538 students grades 8-12 and 507 teachers from 13 schools.

INTERVENTIONS

Serial blood sampling and SARS-CoV-2 IgG antibody assessment.

PRIMARY AND SECONDARY OUTCOME MEASURE

Seroprevalence of SARS-CoV-2 antibodies in study population. Number of undetected cases.

RESULTS

1538 students and 507 teachers were initially enrolled, and 1334 students and 445 teachers completed both study visits. The seroprevalence for SARS-CoV-2 antibodies was 0.6% in May/June and the same in September/October. Even in schools with reported COVID-19 cases before the lockdown of 13 March, no clusters could be identified. Of 12 persons with positive serology five had a known history of confirmed COVID-19; 23 out of 24 participants with a household history of COVID-91 were seronegative.

CONCLUSIONS

Schools do not play a crucial role in driving the SARS-CoV-2 pandemic in a low-prevalence setting. Transmission in families occurs very infrequently, and the number of unreported cases is low in this age group. These observations do not support school closures as a strategy fighting the pandemic in a low-prevalence setting.

TRIAL REGISTRATION NUMBER

DRKS00022455.