Seroprevalence and immunity of SARS-CoV-2 infection in children and adolescents in schools in Switzerland: design for a longitudinal, school-based prospective cohort study

Agne Ulyte,Thomas Radtke,Alexandra Trkola,Jan Fehr,Julia Braun,Milo A Puhan,Susi Kriemler,Ruedi Jung,Sarah R Haile,Irène A Abela,Christoph Berger

doi:10.1007/s00038-020-01495-z

Abstract

ObjectivesThis longitudinal cohort study aims to assess the extent and patterns of seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in school-attending children, and their parents and school personnel. It will examine risk factors for infection, the relationship between seropositivity and symptoms, and temporal persistence of antibodies.MethodsThe study (Ciao Corona) will enroll a regionally representative, random sample of schools in the canton of Zurich, where 18% of the Swiss population live. Children aged 5–16 years, attending primary and secondary schools, and their parents and school personnel are invited. Venous blood and saliva samples are collected for serological testing in June/July 2020, in October/November 2020, and in March/April 2021. Bi-monthly questionnaires will cover SARS-CoV-2 symptoms and tests, health, preventive behavior, and lifestyle information. Hierarchical Bayesian logistic regression models will account for sensitivity and specificity of the serological tests in the analyses and complex sampling structure, i.e., clustering within classes and schools.Results and conclusionsThis unique school-based study will allow describing temporal trends of immunity, evaluate effects of preventive measures and will inform goal-oriented policy decisions during subsequent outbreaks.Trial registration ClinicalTrials.gov Identifier: NCT04448717, registered June 26, 2020. https://clinicaltrials.gov/ct2/show/NCT04448717.

Highlights

Decisions on school openings or closures during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic vary greatly across and within countries
Extended author information available on the last page of the article closures in response to the pandemic were partly guided by evidence of transmission of other viruses, such as influenza (Cauchemez et al 2009; Litvinova et al 2019), but the current reports suggest that the susceptibility and transmissibility of children may be largely different for SARS-CoV-2 (Viner et al 2020)
Lower prevalence of SARS-CoV-2 infection is reported in younger children, which could potentially be explained by less frequent infection or underestimation due to more frequently asymptomatic infection course (Stringhini et al 2020; Gudbjartsson et al 2020; Pollan et al 2020)

Summary

Introduction

Decisions on school openings or closures during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic vary greatly across and within countries. While some countries kept schools mostly open (e.g., Sweden, Australia) or reopened early (e.g., Denmark), others opted for prolonged closures with decisions on reopening pending (e.g., the USA, Italy, Ireland). Extended author information available on the last page of the article closures in response to the pandemic were partly guided by evidence of transmission of other viruses, such as influenza (Cauchemez et al 2009; Litvinova et al 2019), but the current reports suggest that the susceptibility and transmissibility of children may be largely different for SARS-CoV-2 (Viner et al 2020). Children may infect others less often than adults, their exact role in transmission pathways is still not clear (Lee and Raszka 2020)

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