SARS-CoV-2 transmission in educational settings during an early summer epidemic wave in Luxembourg, 2020

Abstract

Background Following a first wave in spring and gradual easing of lockdown, Luxembourg experienced an early second epidemic wave of SARS-CoV-2 before the start of summer school holidays on 15th July. This provided the opportunity to investigate the role of school-age children and school settings for transmission. Methods We compared the incidence of SARS-CoV-2 in school-age children, teachers and the general working population in Luxembourg during two epidemic waves: a spring wave from March–April 2020 corresponding to general lockdown with schools being closed and May–July 2020 corresponding to schools being open. We assessed the number of secondary transmissions occurring in schools between May and July 2020 using routine contact tracing data. Results During the first wave in March–April 2020 when schools were closed, the incidence in pupils peaked at 28 per 100,000, while during the second wave in May–July 2020 when schools were open, incidence peaked 100 per 100,000. While incidence of SARS-CoV-2 was higher in adults than in children during the first spring wave, no significant difference was observed during the second wave in early summer. Between May and July 2020, we identified a total of 390 and 34 confirmed COVID-19 cases among 90,150 school-age children and 11,667 teachers, respectively. We further estimate that 179 primary cases caused 49 secondary cases in schools. While some small clusters of mainly student-to-student transmission within the same class were identified, we did not observe any large outbreaks with multiple generations of infection. Conclusions Transmission of SARS-CoV-2 within Luxembourg schools was limited during an early summer epidemic wave in 2020. Precautionary measures including physical distancing as well as easy access to testing, systematic contact tracing appears to have been successful in mitigating transmission within educational settings.

Schools as a Framework for COVID-19 Epidemiological Surveillance of Children in Catalonia, Spain: A Population-Based Study

“…These studies did not detect SARS-CoV-2 infections in children attending day-care during the onset of the second wave of the pandemic ( 5 ). The same conclusions were obtained in other studies carried out in Luxembourg ( 13 ) and in the United States ( 4 ), in which prevention measures were used to prevent transmission in educational centers. In fact, outbreaks of COVID-19 in educational settings seem rare, and the incidence of infections in these centers reflects that of the general population at the community level ( 33 ).…”

“…The incidence of SARS-CoV-2 infections in educational settings seems to be a reflection of SARS-CoV-2 transmission at the community level ( 13 , 14 ). A study performed in Canada comparing school-related cases and outbreaks of COVID-19 to those in the general population detected more than seventy school clusters, but the weekly incidence of SARS-CoV-2 infection in the schools was always lower than the incidence in the whole population, and the authors concluded that schools were not a significant driver of SARS-CoV-2 transmission ( 15 ), mainly when compared to households ( 16 ).…”

Transmission of SARS-CoV-2 by children and young people in households and schools: A meta-analysis of population-based and contact-tracing studies

“…Lack of clustering is supported by a number of studies not included in our review for quality reasons including a national study from Luxembourg. [71] There may, however, be systematic bias that might contribute to lower transmission in school compared with household studies. For example, CYP who are known to be infected or are contacts of positive cases are usually excluded from school but would be included within household studies.…”

A Statistical Model to Assess Risk for Supporting COVID-19 Quarantine Decisions

“…This search was done with Google Scholar with different combinations of the keywords SARS-CoV-2, COVID-19, transmission, school, pupils, education. As a result, we found four studies that analyzed the transmission probability in school classes: a French study of one school [18], an Irish study of all COVID-19 cases in schools [19], an Australian study [20] analyzing different educational scenarios, and a study in Luxembourg [21].…”

“…This study analyzed an outbreak at a whole school and not in one single school class. The study in Luxembourg analyzed the primary and secondary transmissions in school; however, no information about transmission probability in school classes was reported [21]. Therefore, we decided not to take the last two studies into account.…”