University of Oulu

Marjut Haapanen, Marjo Renko, Miia Artama, Ilari Kuitunen, The impact of the lockdown and the re-opening of schools and day cares on the epidemiology of SARS-CoV-2 and other respiratory infections in children – A nationwide register study in Finland, EClinicalMedicine, Volume 34, 2021, 100807, ISSN 2589-5370,

The impact of the lockdown and the re-opening of schools and day cares on the epidemiology of SARS-CoV-2 and other respiratory infections in children : a nationwide register study in Finland

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Author: Haapanen, Marjut1; Renko, Marjo1,2,3; Artama, Miia4,5;
Organizations: 1School of Medicine, University of Eastern Finland, Yliopistonranta 1, PL 1627, 70211 Kuopio, Finland
2Department of Pediatrics, Kuopio University Hospital, Puijonlaaksontie 2, 70210 Kuopio, Finland
3University of Oulu, PEDEGO Research Unit, Kajaanintie 50, 90220 Oulu, Finland
4Finnish Institute of Health and Welfare, FinnMedi 1, Biokatu 6, 33540 Tampere, Finland
5Faculty of Social Sciences, Tampere University, Arvo Ylpön Katu 34, 33520 Tampere, Finland
6Department of Pediatrics, Mikkeli Central Hospital, Porrassalmenkatu 35-37, 50100 Mikkeli, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.7 MB)
Persistent link:
Language: English
Published: Elsevier, 2021
Publish Date: 2021-05-20


Background: Nationwide restrictions started in Finland in March to prevent the spread of COVID-19, leading to school and day care closures. The aim of this study is to describe the effect of closures and re-openings on the respiratory pathogen epidemiology.

Methods: Laboratory-confirmed cases of SARS-CoV-2; respiratory syncytial virus (RSV); influenza (A & B); parainfluenza-, adeno-, and rhinoviruses; Mycoplasma pneumoniae; and Streptococcus pneumoniae in children were collected from the National Infectious Disease Register over the period of 2017–2020. Weekly incidences (weeks 1 to 35) with 95% confidence intervals (CIs) were calculated per 100 000 children in 2020 and compared by incidence rate ratios (IRRs) to corresponding periods in 2017−2019.

Findings: The lockdown had immediate impact on the incidences of respiratory pathogens except SARS-CoV-2. Week after the lockdown began IRR was 0•3 (CI 0•3–0•4) and next week the IRR was 0•1 (0•1–0•2). The incidence of SARS-CoV-2 started to decline eight weeks after the lockdown began. The highest recorded weekly incidence of SARS-CoV-2 was 7•2/100 000 children. The effect of the lockdown lasted until late summer. Rhinovirus and SARS-CoV-2 began to increase before the schools or day cares opened in August. The re-opening of schools seemed to have no impact on the incidence of any pathogen.

Interpretation: Our results suggest that general social distancing, including school and day care closures, played a crucial role in reducing infections, and the effect lasted for several weeks. The re-opening of schools and day care centres seems to have had no immediate impact on the incidences of any respiratory pathogens.

Funding: This study had no funding source.

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Series: EClinicalMedicine
ISSN: 2589-5370
ISSN-E: 2589-5370
ISSN-L: 2589-5370
Volume: 34
Article number: 100807
DOI: 10.1016/j.eclinm.2021.100807
Type of Publication: A1 Journal article – refereed
Field of Science: 3121 General medicine, internal medicine and other clinical medicine
3123 Gynaecology and paediatrics
Copyright information: © 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (