The Cochrane database of systematic reviewsJan 17, 2022

Actions taken in schools to control the COVID-19 pandemic

Updated Dec 27, 2025

Abstract

Thirty-eight studies were analyzed regarding school measures to manage COVID-19.

Measures in schools could help reduce the spread of SARS-CoV-2 and lower hospitalizations related to COVID-19.
Four main types of measures were identified: reducing contact opportunities, making contacts safer, surveillance and response, and multicomponent strategies.
Many studies showed that reducing contact opportunities, like alternating attendance, generally resulted in fewer cases and hospitalizations, but could lead to fewer school days.
Studies on making contacts safer, such as mask-wearing and cleaning, also indicated reduced transmission and hospitalizations, but had mixed effects on school attendance.
Surveillance measures, including testing and isolation, generally suggested lower hospitalizations and missed school days, but evidence on resource needs was inconsistent.
The overall certainty of evidence is low, implying that actual effects may differ significantly from reported outcomes.

Simplified

BACKGROUND: In response to the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the impact of coronavirus disease 2019 (COVID-19), governments have implemented a variety of measures to control the spread of the virus and the associated disease. Among these, have been measures to control the pandemic in primary and secondary school settings.

OBJECTIVES: To assess the effectiveness of measures implemented in the school setting to safely reopen schools, or keep schools open, or both, during the COVID-19 pandemic, with particular focus on the different types of measures implemented in school settings and the outcomes used to measure their impacts on transmission-related outcomes, healthcare utilisation outcomes, other health outcomes as well as societal, economic, and ecological outcomes. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and the Educational Resources Information Center, as well as COVID-19-specific databases, including the Cochrane COVID-19 Study Register and the WHO COVID-19 Global literature on coronavirus disease (indexing preprints) on 9 December 2020. We conducted backward-citation searches with existing reviews.

SELECTION CRITERIA: We considered experimental (i.e. randomised controlled trials; RCTs), quasi-experimental, observational and modelling studies assessing the effects of measures implemented in the school setting to safely reopen schools, or keep schools open, or both, during the COVID-19 pandemic. Outcome categories were (i) transmission-related outcomes (e.g. number or proportion of cases); (ii) healthcare utilisation outcomes (e.g. number or proportion of hospitalisations); (iii) other health outcomes (e.g. physical, social and mental health); and (iv) societal, economic and ecological outcomes (e.g. costs, human resources and education). We considered studies that included any population at risk of becoming infected with SARS-CoV-2 and/or developing COVID-19 disease including students, teachers, other school staff, or members of the wider community. DATA COLLECTION AND ANALYSIS: Two review authors independently screened titles, abstracts and full texts. One review author extracted data and critically appraised each study. One additional review author validated the extracted data. To critically appraise included studies, we used the ROBINS-I tool for quasi-experimental and observational studies, the QUADAS-2 tool for observational screening studies, and a bespoke tool for modelling studies. We synthesised findings narratively. Three review authors made an initial assessment of the certainty of evidence with GRADE, and several review authors discussed and agreed on the ratings.

MAIN RESULTS: We included 38 unique studies in the analysis, comprising 33 modelling studies, three observational studies, one quasi-experimental and one experimental study with modelling components. Measures fell into four broad categories: (i) measures reducing the opportunity for contacts; (ii) measures making contacts safer; (iii) surveillance and response measures; and (iv) multicomponent measures. As comparators, we encountered the operation of schools with no measures in place, less intense measures in place, single versus multicomponent measures in place, or closure of schools. Across all intervention categories and all study designs, very low- to low-certainty evidence ratings limit our confidence in the findings. Concerns with the quality of modelling studies related to potentially inappropriate assumptions about the model structure and input parameters, and an inadequate assessment of model uncertainty. Concerns with risk of bias in observational studies related to deviations from intended interventions or missing data. Across all categories, few studies reported on implementation or described how measures were implemented. Where we describe effects as 'positive', the direction of the point estimate of the effect favours the intervention(s); 'negative' effects do not favour the intervention. We found 23 modelling studies assessing measures reducing the opportunity for contacts (i.e. alternating attendance, reduced class size). Most of these studies assessed transmission and healthcare utilisation outcomes, and all of these studies showed a reduction in transmission (e.g. a reduction in the number or proportion of cases, reproduction number) and healthcare utilisation (i.e. fewer hospitalisations) and mixed or negative effects on societal, economic and ecological outcomes (i.e. fewer number of days spent in school). We identified 11 modelling studies and two observational studies assessing measures making contacts safer (i.e. mask wearing, cleaning, handwashing, ventilation). Five studies assessed the impact of combined measures to make contacts safer. They assessed transmission-related, healthcare utilisation, other health, and societal, economic and ecological outcomes. Most of these studies showed a reduction in transmission, and a reduction in hospitalisations; however, studies showed mixed or negative effects on societal, economic and ecological outcomes (i.e. fewer number of days spent in school). We identified 13 modelling studies and one observational study assessing surveillance and response measures, including testing and isolation, and symptomatic screening and isolation. Twelve studies focused on mass testing and isolation measures, while two looked specifically at symptom-based screening and isolation. Outcomes included transmission, healthcare utilisation, other health, and societal, economic and ecological outcomes. Most of these studies showed effects in favour of the intervention in terms of reductions in transmission and hospitalisations, however some showed mixed or negative effects on societal, economic and ecological outcomes (e.g. fewer number of days spent in school). We found three studies that reported outcomes relating to multicomponent measures, where it was not possible to disaggregate the effects of each individual intervention, including one modelling, one observational and one quasi-experimental study. These studies employed interventions, such as physical distancing, modification of school activities, testing, and exemption of high-risk students, using measures such as hand hygiene and mask wearing. Most of these studies showed a reduction in transmission, however some showed mixed or no effects. As the majority of studies included in the review were modelling studies, there was a lack of empirical, real-world data, which meant that there were very little data on the actual implementation of interventions.

AUTHORS' CONCLUSIONS: Our review suggests that a broad range of measures implemented in the school setting can have positive impacts on the transmission of SARS-CoV-2, and on healthcare utilisation outcomes related to COVID-19. The certainty of the evidence for most intervention-outcome combinations is very low, and the true effects of these measures are likely to be substantially different from those reported here. Measures implemented in the school setting may limit the number or proportion of cases and deaths, and may delay the progression of the pandemic. However, they may also lead to negative unintended consequences, such as fewer days spent in school (beyond those intended by the intervention). Further, most studies assessed the effects of a combination of interventions, which could not be disentangled to estimate their specific effects. Studies assessing measures to reduce contacts and to make contacts safer consistently predicted positive effects on transmission and healthcare utilisation, but may reduce the number of days students spent at school. Studies assessing surveillance and response measures predicted reductions in hospitalisations and school days missed due to infection or quarantine, however, there was mixed evidence on resources needed for surveillance. Evidence on multicomponent measures was mixed, mostly due to comparators. The magnitude of effects depends on multiple factors. New studies published since the original search date might heavily influence the overall conclusions and interpretation of findings for this review.

Funding

Competing interests

RB: grant/contract from Bundesministerium für Bildung und Forschung. AB: none. JB: grant/contract from German Federal Ministry of Education and Research. MC: grant/contract from Bundesministerium für Bildung und Forschung. KG: grant/contract from German Federal Ministry of Education and Research; Board Member of the German Public Health Association. CJS: German Federal Ministry of Education and Research; I work as a physician (primary tasks: education and research) at the Chair of Public Health, LMU Munich. CaK: grant/contract from German Federal Ministry of Education and Research SuK: grant/contract from Bundesministerium für Bildung und Forschung ClK: none ShK: grant/contract from German Federal Ministry of Education and Research HL: none TL: grant/contract from German Federal Ministry of Education AM: grant/contract from German Federal Ministry of Education and Research LMP: grant/contract from German Federal Ministry of Education and Research JR: grant/contract from German Federal Ministry of Education and Research; I declare being first author of a study on the psychosocial burden in parents of school‐aged children during different phases of the Covid‐19 pandemic in Germany, that was submitted to, but is not yet published by the Journal “Bundesgesundheitsblatt” and might be eligible in future updates of the review. Data for this study were derived from the Covid‐19 Snapshot Monitoring (COSMO) project (https://projekte.uni-erfurt.de/cosmo2020/web/). COSMO is a joint project by the University of Erfurt, the Robert‐Koch‐Institute, the German Federal Agency for Health Education (BZgA), the Leibniz Institute for Psychology, the Science Media Centre, the Bernhard Nocht Institute for Tropical Medicine and the Yale Institute for Public Health. Besides funding from these institutions, funding of the COSMO project derives from the Klaus Tschira Foundation, the Ministry of Economy, Research and Digital Society of Thuringia as well as the state chancellery of Thuringia. ER: grant/contract from Bundesministerium für Bildung und Forschung; a member of the scientific advisory board of the Robert Koch Institute and the Bavarian Health and Food Safety Authority that have both issued guidance on schooling during COVID‐19, but have not been involved with developing this guidance; a member of the WHO Regional Office for Europe’s Technical Advisory Group on Schooling during COVID‐19 and, in this role, is involved with advising the WHO Regional Office for Europe on the issue KS:grant/contract from German Federal Ministry of Education and Research BS: grant/contract from German Federal Ministry of Education and Research JS: grant/contract from Bundesministerium für Bildung und Forschung BV: grant/contract from German Federal Ministry of Education and Research SV: grant/contract from German Federal Ministry of Education and Research KW: grant/contract from German Federal Ministry for Education and Research. RB, KG, CaK, SuK, AM, LMP, JR, ER, KS, BS, JS, BV, SV, KW declare being part of the scientific secretariat that supports the development of a living interdisciplinary, evidence‐based and consensus‐based guideline on measures to prevent and control SARS‐CoV‐2 transmission in schools, registered with the Association of the Scientific Medical Societies (AWMF) in Germany (www.awmf.org/en/clinical-practice-guidelines/detail/anmeldung/1/ll/027-076.html). CJS, AM and ER are involved in the conduct of an ongoing study that, after completion, is likely to be eligible for inclusion in the review (COVID Kids Bavaria, funded by the State of Bavaria, Germany).

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Abstract

Funding

Competing interests

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