Unintended consequences of school-based measures to manage the COVID-19 pandemic

Why is this question important?

Countries worldwide have taken many public health and social measures to prevent and control the spread of SARS-CoV-2, a highly contagious respiratory virus responsible for COVID-19. A range of measures have been put in place to minimise transmission of SARS-CoV-2 within schools and the wider community. Schools have the potential to be settings of high viral transmission because they involve extended interactions amongst people in close proximity. A previous review located and examined studies on the effectiveness of such school-based measures regarding SARS-CoV-2 transmission. It is equally important to look at their unintended consequences on health and society in order that policymakers and parents can make informed decisions. Unintended consequences of a public health measure may be beneficial or harmful (or a mix of both). A public health measure may result in a mix of benefits and harms. For this review, we planned to examine the unintended consequences of measures designed to prevent and control the spread of SARS-CoV-2 in schools. This review can therefore be seen as complementing the previous review on the effectiveness of such measures.   

What did we do?

Firstly, we searched nine databases for studies that assessed any measure put in place in the school settings (primary or secondary schools, or both) to prevent transmission of the virus. We considered all types of studies and a broad range of outcomes.

Secondly, we grouped the identified studies according to the types of measures they examined. We then described which approaches were used in the studies, where these were conducted, and which unintended consequences were evaluated. 

What did we find?

We found 18 studies that matched our inclusion criteria. Five studies used ‘real-life’ data (observational studies); five studies used data generated by a computer and based on a set of assumptions (modelling studies); three studies were experimental studies (e.g. laboratory-based); and four studies used qualitative methods, meaning they based their findings on interviews with people. One study used mixed methods, combining numerical and non-numerical (qualitative) information. 

Studies examined four different types of measures, as follows.

- Measures to reduce contacts (4 studies): policies to reduce the number of students in the school building (i.e. reducing the number of students present per class) and/or to reduce the number of contacts of students (e.g. through defined groups or staggered arrival, breaks, and departures).

- Measures to make contacts safer (14 studies): practices to ensure safer contacts between people in the school and classroom setting (e.g. mask mandates or distancing regulations), to modify the environment or activities (e.g. enhanced cleaning or ventilation practices).

- Surveillance and response measures to detect SARS-CoV-2 infections (6 studies): testing and/or screening strategies (e.g. temperature taking, screening tests for students and staff, and testing of symptomatic students and staff) and self-isolation or quarantine measures.

- Multicomponent measures (1 study): interventions using a combination of at least two of the above measures.

We looked at the following unintended outcomes.

- Educational consequences (11 studies), e.g. changes in school performance, advancement to the next grade, or change in graduation numbers.

- Psychosocial outcomes (7 studies), e.g. mental health, anxieties about going to school.

- Physical health and health behaviour outcomes beyond COVID-19 (3 studies), e.g. hand eczema due to increased handwashing.

- Environmental consequences (3 studies), e.g. changes in air quality in classrooms.

- Socio-economic consequences (2 studies), e.g. economic burden on families. 

What did we conclude?

We identified a wide range of unintended consequences of school-based measures designed to prevent the spread of SARS-CoV-2. However, the evidence base is small, and there are large gaps where more research is needed. This scoping review is a first step in gauging the extent of those consequences. More research is needed to collect additional information and to enable a more thorough analysis of the evidence. Psychosocial consequences (e.g. mental health issues, depression, loneliness) and equity and equality consequences (e.g. disadvantages for children from low-income households, unfair distribution of work between genders for parents, are in need of further attention. We recommend that future research look at interventions such as fixed groups, alternating physical presence at school and staggered arrival departure and break times, as well as testing and quarantine measures. 

How up to date is this evidence?

The evidence is up to date to March 2021.

Authors' conclusions: 

We identified a heterogeneous evidence base on unintended consequences of measures implemented in the school setting to prevent and control the spread of SARS-CoV-2, and summarised the available study data narratively and graphically. Primary research better focused on specific measures and various unintended outcomes is needed to fill knowledge gaps and give a broader picture of the diverse unintended consequences of school-based measures before a more thorough evidence synthesis is warranted. The most notable lack of evidence we found was regarding psychosocial, equity, and equality outcomes. We also found a lack of research on interventions that aim to reduce the opportunity for contacts. Additionally, study investigators should provide sufficient data on contextual factors and demographics in order to ensure analyses of such are feasible, thus assisting stakeholders in making appropriate, informed decisions for their specific circumstances.

Read the full abstract...

With the emergence of SARS-CoV-2 in late 2019, governments worldwide implemented a multitude of non-pharmaceutical interventions in order to control the spread of the virus. Most countries have implemented measures within the school setting in order to reopen schools or keep them open whilst aiming to contain the spread of SARS-CoV-2. For informed decision-making on implementation, adaptation, or suspension of such measures, it is not only crucial to evaluate their effectiveness with regard to SARS-CoV-2 transmission, but also to assess their unintended consequences.


To comprehensively identify and map the evidence on the unintended health and societal consequences of school-based measures to prevent and control the spread of SARS-CoV-2. We aimed to generate a descriptive overview of the range of unintended (beneficial or harmful) consequences reported as well as the study designs that were employed to assess these outcomes. This review was designed to complement an existing Cochrane Review on the effectiveness of these measures by synthesising evidence on the implications of the broader system-level implications of school measures beyond their effects on SARS-CoV-2 transmission.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, four non-health databases, and two COVID-19 reference collections on 26 March 2021, together with reference checking, citation searching, and Google searches.

Selection criteria: 

We included quantitative (including mathematical modelling), qualitative, and mixed-methods studies of any design that provided evidence on any unintended consequences of measures implemented in the school setting to contain the SARS-CoV-2 pandemic. Studies had to report on at least one unintended consequence, whether beneficial or harmful, of one or more relevant measures, as conceptualised in a logic model. 

Data collection and analysis: 

We screened the titles/abstracts and subsequently full texts in duplicate, with any discrepancies between review authors resolved through discussion. One review author extracted data for all included studies, with a second review author reviewing the data extraction for accuracy. The evidence was summarised narratively and graphically across four prespecified intervention categories and six prespecified categories of unintended consequences; findings were described as deriving from quantitative, qualitative, or mixed-method studies.

Main results: 

Eighteen studies met our inclusion criteria. Of these, 13 used quantitative methods (3 experimental/quasi-experimental; 5 observational; 5 modelling); four used qualitative methods; and one used mixed methods. Studies looked at effects in different population groups, mainly in children and teachers. The identified interventions were assigned to four broad categories: 14 studies assessed measures to make contacts safer; four studies looked at measures to reduce contacts; six studies assessed surveillance and response measures; and one study examined multiple measures combined. Studies addressed a wide range of unintended consequences, most of them considered harmful. Eleven studies investigated educational consequences. Seven studies reported on psychosocial outcomes. Three studies each provided information on physical health and health behaviour outcomes beyond COVID-19 and environmental consequences. Two studies reported on socio-economic consequences, and no studies reported on equity and equality consequences.