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. 2021 Apr:34:100807.
doi: 10.1016/j.eclinm.2021.100807. Epub 2021 Mar 29.

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

Marjut Haapanen  1 , Marjo Renko  1   2   3 , Miia Artama  4   5 , Ilari Kuitunen  1   6
Affiliations

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

Marjut Haapanen et al. EClinicalMedicine. 2021 Apr.

Abstract

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.

Keywords: COVID-19; Public health; Register study; Social distancing.

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Conflict of interest statement

None of the authors have any potential competing interests to declare.

Figures

Fig. 1
Fig. 1
Incidences of laboratory-confirmed respiratory pathogens in relation to school and day care closures and summer vacation among 0-to-14-year-old patients. SARS-CoV-2 infections among 0-to-19-year-old patients. The grey area presents the numbers of weekly SARS-CoV-2 PCR tests performed in Finland on patients of all ages. Pink boxes indicate the school and day care closures in the spring and summer vacation periods.
Fig. 2
Fig. 2
Weekly incidences of respiratory pathogens in 2020 in comparison to mean weekly incidences from 2017 to 2019. Children aged 0–14 years are included, and for SARS-CoV-2, children aged 0–19 years are included in the analysis. Pink boxes indicate the school and day care closures in the spring and summer vacation periods.
Fig. 3
Fig. 3
Weekly incidences of respiratory pathogens per 100 000 children grouped by age in 2020. Age groups are 0–4, 5–9 and 10–14 years for RSV; influenza (A & B); parainfluenza-, adeno-, and rhinoviruses; Mycoplasma pneumoniae; and Streptococcus pneumoniae. SARS-CoV-2 grouped to 0–9 and 10–19 years due to register design. Pink boxes indicate the school and day care closures in the spring and summer vacation periods.
See this image and copyright information in PMC

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