Background School attendance during the COVID-19 pandemic is intensely debated. Aim In November 2020, we assessed SARS-CoV-2 infections and seroreactivity in 24 randomly selected school classes and connected households in Berlin, Germany. Methods We collected oro-nasopharyngeal swabs and blood samples, examining SARS-CoV-2 infection and IgG antibodies by RT-PCR and ELISA. Household members self-swabbed. We assessed individual and institutional prevention measures. Classes with SARS-CoV-2 infection and connected households were retested after 1 week. Results We examined 1,119 participants, including 177 primary and 175 secondary school students, 142 staff and 625 household members. SARS-CoV-2 infection occurred in eight classes, affecting each 1–2 individuals. Infection prevalence was 2.7% (95% confidence interval (CI): 1.2–5.0; 9/338), 1.4% (95% CI: 0.2–5.1; 2/140), and 2.3% (95% CI: 1.3–3.8; 14/611) among students, staff and household members. Six of nine infected students were asymptomatic at testing. We detected IgG antibodies in 2.0% (95%CI: 0.8–4.1; 7/347), 1.4% (95% CI: 0.2–5.0; 2/141) and 1.4% (95% CI: 0.6–2.7; 8/576). Prevalence increased with inconsistent facemask-use in school, walking to school, and case-contacts outside school. For three of nine households with infection(s), origin in school seemed possible. After 1 week, no school-related secondary infections appeared in affected classes; the attack rate in connected households was 1.1%. Conclusion School attendance under rigorously implemented preventive measures seems reasonable. Balancing risks and benefits of school closures need to consider possible spill-over infection into households. Deeper insight is required into the infection risks due to being a schoolchild vs attending school.

N-3 polyunsaturated fatty acids (PUFAs) have been suggested to affect depressive disorders. This review aims to determine the effect of n-3 PUFAs on depressive symptoms in people with or without diagnosed depression. Medline, PsycINFO, and Cochrane CENTRAL databases were searched for randomized controlled trials (RCTs) assessing the association between n-3 PUFAs and depressive symptoms or disorders as outcomes. A random-effects meta-analysis of standardized mean difference (SMD) with 95% confidence intervals (CI) was performed. Twenty-five studies (7682 participants) were included. Our meta-analysis (20 studies) indicated that n-3 PUFA supplementation lowered depressive symptomology as compared with placebo: SMD = −0.34, 95% CI: −0.55, −0.12, I2 = 86%, n = 5836, but a possible publication bias cannot be ruled out. Subgroup analyses indicated no statistically significant difference by treatment duration of <12 vs. ≥12 weeks, presence of comorbidity, or severity of depressive symptoms. Nevertheless, beneficial effects were seen in the subgroups of studies with longer treatment duration and with no depression and mild to moderate depression. Subgroup analysis by eicosapentaenoic acid (EPA) dosage revealed differences in favor of the lower EPA dosage. Sensitivity analysis including studies with low risk of bias seems to confirm the overall result. Supplementation of n-3 PUFA appears to have a modest beneficial effect on depressive symptomology, although the quality of evidence is still insufficient.

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.