Measures for infection prevention and control of SARS-CoV-2 in Belgian schools between December 2020 and June 2021: a prospective cohort study

Abstract

Introduction: As the role of school-aged children was unclear at the onset of the COVID-19 pandemic, public health authorities recommended to implement infection prevention and control (IPC) measures in school settings. Few studies evaluated the implementation of these measures and their effect on SARS-CoV-2 infection rates among pupils and staff. Aim: To describe the implementation of IPC measures in Belgian primary and secondary schools and assess its relation to the prevalence of anti-SARS-CoV-2 antibodies among pupils and staff. Methods: We conducted a prospective cohort study in a representative sample of primary and secondary schools in Belgium. Implementation of IPC measures in schools was assessed using an online questionnaire. Saliva samples were collected from pupils and staff to determine the SARS-CoV-2 seroprevalence. Results: A variety of IPC measures (ventilation, hygiene and physical distancing) was implemented by more than 60% of primary and secondary schools with most attention for hygiene measures. Almost no differences in implementation coverage were observed between primary and secondary schools or the Dutch and French language network. Poor implementation of IPC measures was associated with an increased anti-SARS-CoV-2 antibody prevalence among pupils from 8.6% (95% CI: 4.5 - 16.6) to 16.7% (95% CI: 10.2 - 27.4) and staff from 11.5% (95% CI: 8.1 - 16.4) to 17.6% (95% CI: 11.5 - 27.0). This association was statistically significant for all IPC measures and pupils and staff combined. Conclusion: Belgian schools were relatively compliant with recommended IPC measures at the school level. Poor implementation of IPC measures was associated with higher SARS-CoV-2 seroprevalence among pupils and staff.

Reconstruction of SARS-CoV-2 outbreaks in a primary school using epidemiological and genomic data

“…In the present study SARS-CoV-2 infection was equally present among adults and children, consistent with findings from previous studies [7, 10, 22]. We found no significant difference in the proportion of asymptomatic cases between children and adults during the second part of the study, while it was observed that children were more often asymptomatic during September – December 2020 [10].…”

“…In addition to structural interventions such as improving air quality in schools through better ventilation systems [6, 7], screening protocols such as repetitive and reactive screening can also aid in preventing the occurrence of large school outbreaks and consequent closures. In reactive screening, a classroom is tested and quarantined after a certain number of cases is observed, whereas in repetitive screening the entire classroom is tested regularly, regardless of whether a case is observed or not.…”

Comparison of SARS-CoV-2 seroconversion in children with chronic diseases with healthy children and adults during the first waves of the COVID-19 pandemic

“…To have the most relevant comparison, we only used the reported seroprevalence collected from persons living in the same geographic region as our patients and filtered on data collected during the same period as our study. Estimated seroprevalence from healthy children was obtained from longitudinal studies in Belgian schools (16)(17)(18)(19), which used a validated serology test in saliva (20). We only used data from pupils from Flemish primary schools to ensure demographic matching with our cohort (these pupils were non-vaccinated during the entire study period).…”

“…None had known primary or secondary immune deficiency. To compare our pediatric data, a surveillance study measuring seroconversion in pupils from schools is plotted (green) (16)(17)(18)(19). For this healthy pediatric cohort, we used the readily available and substratified data from the subnational level (Flanders) and concerning children from primary school, to maximally match our cohort of patients.…”