SARS-CoV-2 infection and transmission in school settings during the second wave in Berlin, Germany: a cross-sectional study

Abstract

BackgroundSchool attendance during the SARS-CoV-2 pandemic is intensely debated. Modelling studies suggest that school closures contribute to community transmission reduction. However, data among school-attending students and staff are scarce. In November 2020, we examined SARS-CoV-2 infections and seroreactivity in 24 randomly selected school classes and connected households in Berlin, Germany.MethodsStudents and school staff were examined, oro-nasopharyngeal swabs and blood samples collected, and SARS-CoV-2 infection and IgG antibodies detected by RT-PCR and ELISA. Household members performed self-swabs. Individual and institutional infection prevention and control measures were assessed. Classes with SARS-CoV-2 infection and connected household members were re-tested after one week.Findings1119 participants were examined, including 177 primary and 175 secondary school students, 142 staff, and 625 household members. Participants reported mainly cold symptoms (19·4%). SARS-CoV-2 infection occurred in eight of 24 classes affecting each 1-2 individuals. Infection prevalence was 2·7% (95%CI; 1·2-5·0%; 9/338), 1·4% (0·2-5·1%; 2/140), and 2·3% (1·3-3·8%; 14/611) among students, staff and household members, respectively, including quarantined persons. Six of nine infected students were asymptomatic. Prevalence increased with inconsistent facemask use in school, way to school on foot, and case-contacts outside school. IgG antibodies were detected in 2·0% (0·8-4·1%; 7/347), 1·4% (0·2-5·0%; 2/141) and 1·4% (0·6-2·7%; 8/576), respectively. For three of nine households with infection(s) detected at cross-sectional assessment, origin in school seemed possible. After one week, no school-related, secondary infections appeared in affected classes; the attack rate in connected households was 1·1%.InterpretationThese data suggest that school attendance under preventive measures is feasible, provided their rigorous implementation. In balancing threats and benefits of open versus closed schools during the pandemic, parents and society need to consider possible spill-overs into their households. Deeper insight is needed into the infection risks due to being a schoolchild as compared to attending school.FundingSenate of Berlin.

SARS-CoV-2 screening prevalence in educational staff in Berlin, Germany, June-December 2020

“…In another study at peak transmission in Berlin, early November 2020, 1.4% of 140 teachers were found to be infected [4], confirming our findings.…”

“…Such concerns, in turn, impact on the functionality of schooling and childcare [1]. While the influence of opened or closed educational facilities on the course of the pandemic has been subject to modelling [2] and observational studies [3][4], with partially contradicting findings, the actual occupational risk of educational staff is less clear. Repeatedly changing infection prevention and control (IPC) measures, such as to mask wearing obligations or divided classes, also make it difficult to draw firm conclusions.…”

Promoting Factfulness in the Covid-19 pandemic-related policymaking: a map to understanding school closures

“…Recent empirical work from multiple countries that correlates school re-opening to local Rt direction changes and secondary infection clusters increasingly confirms earlier findings of minimal contribution of educational settings to the community COVID-19 growth rates [36][37][38][52][53][54]: open schools of all grades may be considered safe and will not act as amplifiers of Sars-CoV-2 spread at times of low COVID-19 background prevalence. In fact, it appears that adults, and not children, play a key role in bringing the virus into their households [39,55], and that in-school COVID-19 incidence is directly consequential to local background prevalence [40,41,56,57].…”

“…Furthermore, as synthesized in a large systematic review [47], multiple organizational, environmental and surveillance measures have been implemented heterogeneously worldwide to minimize the risk of in-class infection, including highly effective test-and-trace strategies, decreased class size, opening for specific cohorts in a staggered timetable, lessons held outdoors, physical distancing as well as hygiene measures in the classroom, the creation of social bubbles limiting contacts between those who rarely meet, and the instruction to stay at home when sick [48][49][50]. Although successfully curtailed school-related outbreaks are less likely to be reported in the literature than outbreaks that have occurred, we have sufficient real-world evidence indicating that different types of infection control measures may effectively either avert or minimalize COVID-19 clusters among students [51][52][53][54]. While the efficacy of each measure has been extensively modelled, very few experimental and quasi-experimental studies have been published assessing the effectiveness of specific measures, including one finding that lower physical distancing policies may safely be adopted in school settings [55].…”

Seroprevalence of anti-SARS-CoV-2 antibodies among school and daycare children and personnel: protocol for a cohort study in Montreal, Canada

“…11 Longitudinal seroprevalence studies conducted in schools are beginning to advance our knowledge of school-based SARS-CoV-2 transmission among children, staff and families. [14][15][16] For example, studies conducted in French 17 and British 16 primary schools suggested little evidence of transmission from children to their peers or teachers, while a large Swiss cohort 18 found minimal clustering of seropositive cases within classes and schools despite a clear increase in seroprevalence in children over a 5-month period of very high transmission.…”