Lorthe, Elsa, Bellon, Mathilde, Michielin, Gregoire, Berthelot, Julie, Zaballa, Maria-Eugenia, Pennacchio, Francesco, Bekliz, Meriem, Laubscher, Florian, Arefi, Fatemeh, Perez-Saez, Javier, Azman, Andrew S., L'Huillier, Arnaud G., Posfay-Barbe, Klara M., Kaiser, Laurent, Guessous, Idris, Maerkl, Sebastian J., Eckerle, Isabella, and Stringhini, Silvia
Objectives, To report a prospective epidemiological, virological and serological investigation of a SARS-CoV-2 outbreak in a primary school., Methods, As part of a longitudinal, prospective, school-based surveillance study, this investigation involved repeated testing of 73 pupils, 9 teachers, 13 non-teaching staff and 26 household members of participants who tested positive, with rapid antigen tests and/or RT-PCR (Day 0-2 and Day 5-7), serologies on dried capillary blood samples (Day 0-2 and Day 30), contact tracing interviews and SARS-CoV-2 whole genome sequencing., Results, We identified 20 children (aged 4 to 6 years from 4 school classes), 2 teachers and a total of 4 household members who were infected by the Alpha variant during this outbreak. Infection attack rates were between 11.8 and 62.0% among pupils from the 4 school classes, 22.2% among teachers and 0% among non-teaching staff. Secondary attack rate among household members was 15.4%. Symptoms were reported by 63% of infected children, 100% of teachers and 50% of household members. All analysed sequences but one showed 100% identity. Serological tests detected 8 seroconversions unidentified by SARS-CoV-2 virological tests., Conclusions, This study confirmed child-to-child and child-to-adult SARS-CoV-2 transmission and introduction into households. Effective measures to limit transmission in schools have the potential to reduce the overall community circulation.