Do school closures and school reopenings affect community transmission of COVID-19? A systematic review of observational studies

Measures implemented in the school setting to contain the COVID-19 pandemic

BACKGROUND

More than 767 million coronavirus 2019 (COVID-19) cases and 6.9 million deaths with COVID-19 have been recorded as of August 2023. Several public health and social measures were implemented in schools to contain the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and prevent onward transmission. We built upon methods from a previous Cochrane review to capture current empirical evidence relating to the effectiveness of school measures to limit SARS-CoV-2 transmission.

OBJECTIVES

To provide an updated assessment of the evidence on the effectiveness of measures implemented in the school setting to keep schools open safely during the COVID-19 pandemic.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register, Educational Resources Information Center, World Health Organization (WHO) COVID-19 Global literature on coronavirus disease database, and the US Department of Veterans Affairs Evidence Synthesis Program COVID-19 Evidence Reviews on 18 February 2022.

SELECTION CRITERIA

Eligible studies focused on measures implemented in the school setting to contain the COVID-19 pandemic, among students (aged 4 to 18 years) or individuals relating to the school, or both. We categorized studies that reported quantitative measures of intervention effectiveness, and studies that assessed the performance of surveillance measures as either 'main' or 'supporting' studies based on design and approach to handling key confounders. We were interested in transmission-related outcomes and intended or unintended consequences.

DATA COLLECTION AND ANALYSIS

Two review authors screened titles, abstracts and full texts. We extracted minimal data for supporting studies. For main studies, one review author extracted comprehensive data and assessed risk of bias, which a second author checked. We narratively synthesized findings for each intervention-comparator-outcome category (body of evidence). Two review authors assessed certainty of evidence.

MAIN RESULTS

The 15 main studies consisted of measures to reduce contacts (4 studies), make contacts safer (7 studies), surveillance and response measures (6 studies; 1 assessed transmission outcomes, 5 assessed performance of surveillance measures), and multicomponent measures (1 study). These main studies assessed outcomes in the school population (12), general population (2), and adults living with a school-attending child (1). Settings included K-12 (kindergarten to grade 12; 9 studies), secondary (3 studies), and K-8 (kindergarten to grade 8; 1 study) schools. Two studies did not clearly report settings. Studies measured transmission-related outcomes (10), performance of surveillance measures (5), and intended and unintended consequences (4). The 15 main studies were based in the WHO Regions of the Americas (12), and the WHO European Region (3). Comparators were more versus less intense measures, single versus multicomponent measures, and measures versus no measures. We organized results into relevant bodies of evidence, or groups of studies relating to the same 'intervention-comparator-outcome' categories. Across all bodies of evidence, certainty of evidence ratings limit our confidence in findings. Where we describe an effect as 'beneficial', the direction of the point estimate of the effect favours the intervention; a 'harmful' effect does not favour the intervention and 'null' shows no effect either way. Measures to reduce contact (4 studies) We grouped studies into 21 bodies of evidence: moderate- (10 bodies), low- (3 bodies), or very low-certainty evidence (8 bodies). The evidence was very low to moderate certainty for beneficial effects of remote versus in-person or hybrid teaching on transmission in the general population. For students and staff, mostly harmful effects were observed when more students participated in remote teaching. Moderate-certainty evidence showed that in the general population there was probably no effect on deaths and a beneficial effect on hospitalizations for remote versus in-person teaching, but no effect for remote versus hybrid teaching. The effects of hybrid teaching, a combination of in-person and remote teaching, were mixed. Very low-certainty evidence showed that there may have been a harmful effect on risk of infection among adults living with a school student for closing playgrounds and cafeterias, a null effect for keeping the same teacher, and a beneficial effect for cancelling extracurricular activities, keeping the same students together and restricting entry for parents and caregivers. Measures to make contact safer (7 studies) We grouped studies into eight bodies of evidence: moderate- (5 bodies), and low-certainty evidence (3 bodies). Low-certainty evidence showed that there may have been a beneficial effect of mask mandates on transmission-related outcomes. Moderate-certainty evidence showed full mandates were probably more beneficial than partial or no mandates. Evidence of a beneficial effect of physical distancing on risk of infection among staff and students was mixed. Moderate-certainty evidence showed that ventilation measures probably reduce cases among staff and students. One study (very low-certainty evidence) found that there may be a beneficial effect of not sharing supplies and increasing desk space on risk of infection for adults living with a school student, but showed there may be a harmful effect of desk shields. Surveillance and response measures (6 studies) We grouped studies into seven bodies of evidence: moderate- (3 bodies), low- (1 body), and very low-certainty evidence (3 bodies). Daily testing strategies to replace or reduce quarantine probably helped to reduce missed school days and decrease the proportion of asymptomatic school contacts testing positive (moderate-certainty evidence). For studies that assessed the performance of surveillance measures, the proportion of cases detected by rapid antigen detection testing ranged from 28.6% to 95.8%, positive predictive value ranged from 24.0% to 100.0% (very low-certainty evidence). There was probably no onward transmission from contacts of a positive case (moderate-certainty evidence) and replacing or shortening quarantine with testing may have reduced missed school days (low-certainty evidence). Multicomponent measures (1 study) Combining multiple measures may have led to a reduction in risk of infection among adults living with a student (very low-certainty evidence).

AUTHORS' CONCLUSIONS

A range of measures can have a beneficial effect on transmission-related outcomes, healthcare utilization and school attendance. We rated the current findings at a higher level of certainty than the original review. Further high-quality research into school measures to control SARS-CoV-2 in a wider variety of contexts is needed to develop a more evidence-based understanding of how to keep schools open safely during COVID-19 or a similar public health emergency.

What is the specific role of schools and daycares in COVID-19 transmission? A final report from a living rapid review

Due to rapidly evolving conditions, the question of how to safely operate schools and daycares remained a top priority throughout the COVID-19 pandemic. In response to growing and changing evidence, the National Collaborating Centre for Methods and Tools in Canada maintained a living rapid review on the role of schools and daycares in COVID-19 transmission to guide evidence-informed decision making. This Review presents the final iteration of this living rapid review. 31 sources were searched until Oct 17, 2022. In the final version, eligible studies reported data from Jan 1, 2021 onward on transmission of COVID-19 in school or daycare settings, the effect of infection prevention and control measures on transmission, or the effect of operating schools or daycares on community-level COVID-19 rates. As a rapid review, titles and abstracts were screened by a single reviewer with artificial intelligence integrated into later versions. Full-text screening, data extraction, and critical appraisal were completed by one reviewer and checked by a second reviewer. The Johanna Briggs Institute tools were used for critical appraisal. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach, and results were synthesised narratively. Three citizen partners provided input for the final interpretation. This final update includes 73 primary studies. Secondary attack rates were low within school settings when infection prevention and control measures were in place (moderate certainty). Masks might reduce transmission, test-to-stay policies might not increase transmission risk compared with mandatory quarantine, cohorting and hybrid learning might make little to no difference in transmission (low certainty), and the effect of surveillance testing within schools remained inconclusive (very low certainty). Findings indicate that school settings do not substantially contribute to community incidence, hospitalisations, or mortality (low certainty). This living review provides a synthesis of global evidence for the role of schools and daycares during COVID-19, which might be helpful in future pandemics.

Impact of alternative Non-Pharmaceutical Interventions strategies for controlling COVID-19 outbreak in Bangladesh: A modeling study

The COVID-19 pandemic has been a major health concern in Bangladesh until very recently. Although the Bangladesh government has employed various infection control strategies, more targeted Non-Pharmaceutical interventions (NPIs), including school closure, mask-wearing, hand washing, and social distancing have gained special attention. Despite significant long-term adverse effects of school closures, authorities have opted to keep schools closed to curb the spread of COVID-19 infection. However, there is limited knowledge about the impact of reopening schools alongside other NPI measures on the course of the epidemic. In this study, we implemented a mathematical modeling framework developed by the CoMo Consortium to explore the impact of NPIs on the dynamics of the COVID-19 outbreak and deaths for Bangladesh. For robustness, the results of prediction models are then validated through model calibration with incidence and mortality data and using external sources. Hypothetical projections are made under alternative NPIs where we compare the impact of current NPIs with school closures versus enhanced NPIs with school openings. Results suggest that enhanced NPIs with schools opened may have lower COVID-19 related prevalence and deaths. This finding indicates that enhanced NPIs and school openings may mitigate the long-term negative impacts of COVID-19 in low- and middle-income countries. Potential shortcomings and ways to improve the research are also discussed.

Anxiety disorders among children and adolescents during COVID-19 lockdowns and school closures: a cross-sectional study in Kuwait

Introduction

Investigating the epidemiology of mental health disorders resulting from COVID-19 intervention measures, primary school closures, and social isolation in children and adolescents needs to be prioritized over adults at the post-pandemic stage. Most preliminary psychosocial studies conducted during the pandemic have demonstrated that younger age groups are the most vulnerable to such implications. Thus, this study aims to estimate the probable prevalence of specific anxiety disorders in children and quantify their relationships with relevant demographic risk factors.

Methods

We used a cross-sectional study comprising 430 children aged between 8- and 18 years old living in Kuwait during the period of school closures as well as full and partial lockdowns. The survey included questions about participants' characteristics, children's anxiety using the Screen for Child Anxiety Related Emotional Disorders Questionnaire (SCARED) scale, and children's emotions and behaviours using the Strengths and Difficulties Questionnaire (SDQ). Univariate and multivariate logistic regression analyses were used to summarize the demographic and characteristics of the participants and their association with general, social, and generalized anxieties, as well as behavioural and emotional difficulties.

Results

We inferred that 24.83% of our participants had at least one anxiety disorder, while 20.19% were classified as abnormal on the SDQ scale. Our multivariate analysis revealed that lockdown duration and sex of the child were consistently significant predictors (p-values < 0.05) of the broad spectrum of selected mental disorders. Additionally, we inferred notable increases in the likelihood of mental disorders associated with the increased duration of lockdowns.

Conclusions

Our findings revealed preliminary insights into the vulnerability of young populations to the indirect negative impacts of strict public health measures during pandemic emergencies. Thus, authorities should consider such implications when planning and implementing similar interventions in future pandemics.

Airborne transmission risks of tuberculosis and COVID-19 in schools in South Africa, Switzerland, and Tanzania: Modeling of environmental data

The COVID-19 pandemic renewed interest in airborne transmission of respiratory infections, particularly in congregate indoor settings, such as schools. We modeled transmission risks of tuberculosis (caused by Mycobacterium tuberculosis, Mtb) and COVID-19 (caused by SARS-CoV-2) in South African, Swiss and Tanzanian secondary schools. We estimated the risks of infection with the Wells-Riley equation, expressed as the median with 2.5% and 97.5% quantiles (credible interval [CrI]), based on the ventilation rate and the duration of exposure to infectious doses (so-called quanta). We computed the air change rate (ventilation) using carbon dioxide (CO2) as a tracer gas and modeled the quanta generation rate based on reported estimates from the literature. The share of infectious students in the classroom is determined by country-specific estimates of pulmonary TB. For SARS-CoV-2, the number of infectious students was estimated based on excess mortality to mitigate the bias from country-specific reporting and testing. Average CO2 concentration (parts per million [ppm]) was 1,610 ppm in South Africa, 1,757 ppm in Switzerland, and 648 ppm in Tanzania. The annual risk of infection for Mtb was 22.1% (interquartile range [IQR] 2.7%-89.5%) in South Africa, 0.7% (IQR 0.1%-6.4%) in Switzerland, and 0.5% (IQR 0.0%-3.9%) in Tanzania. For SARS-CoV-2, the monthly risk of infection was 6.8% (IQR 0.8%-43.8%) in South Africa, 1.2% (IQR 0.1%-8.8%) in Switzerland, and 0.9% (IQR 0.1%-6.6%) in Tanzania. The differences in transmission risks primarily reflect a higher incidence of SARS-CoV-2 and particularly prevalence of TB in South Africa, but also higher air change rates due to better natural ventilation of the classrooms in Tanzania. Global comparisons of the modeled risk of infectious disease transmission in classrooms can provide high-level information for policy-making regarding appropriate infection control strategies.

The effect of smaller classes on infection-related school absence: evidence from the Project STAR randomized controlled trial

BACKGROUND

In an effort to reduce viral transmission, many schools reduced class sizes during the recent pandemic. Yet the effect of class size on transmission is unknown.

METHODS

We used data from Project STAR, a randomized controlled trial in which 10,816 Tennessee elementary students were assigned at random to smaller classes (13 to 17 students) or larger classes (22 to 26 students) in 1985-89. We merged Project STAR schools with data on local deaths from pneumonia and influenza in the 122 Cities Mortality Report System. Using mixed effects linear, Poisson, and negative binomial regression, we estimated the main effect of smaller classes on absence. We used an interaction to test whether the effect of small classes on absence was larger when and where community pneumonia and influenza prevalence was high.

RESULTS

Small classes reduced absence by 0.43 days/year (95% CI -0.06 to -0.80, p < 0.05), but small classes had no significant interaction with community pneumonia and influenza mortality (95% CI -0.27 to + 0.30, p > 0.90), indicating that the reduction in absence due to small classes was not larger when community disease prevalence was high.

CONCLUSION

Small classes reduced absence, but the reduction was not larger when disease prevalence was high, so the reduction in absence was not necessarily achieved by reducing infection. Small classes, by themselves, may not suffice to reduce the spread of respiratory viruses.

Impact of "Long Covid" on Children: Global and Hong Kong Perspectives

BACKGROUND

The coronavirus disease (COVID-19) pandemic spares no nation or city, and the virus is responsible for the escalating incidence and mortality worldwide.

OBJECTIVE

This article reviews the impact of "Long Covid" on Children.

METHODS

A PubMed search was conducted in December 2021 in Clinical Queries using the key terms "COVID-19" OR "long COVID". The search was restricted to children and adolescent aged < 18 years and English literature.

RESULTS

Many large-scale studies have provided strong scientific evidence as to the detrimental and irreversible sequelae of COVID-19 on the health, psychology, and development of affected children. Many insights into managing this disease can be obtained from comparing the management of influenza. COVID-19 is generally a mild respiratory disease in children. Several syndromes, such as multisystem inflammatory syndrome in children (MIS-C) and COVID toe, are probably not specific to SARS-CoV-2. "Long COVID", or the long-term effects of SARS-CoV-2 infection, or the prolonged isolation and containment strategies on education and psychosocial influences on children associated with the pandemic, are significant.

CONCLUSION

Healthcare providers must be aware of the potential effects of quarantine on children's mental health. More importantly, healthcare providers must appreciate the importance of the decisions and actions made by governments, non-governmental organizations, the community, schools, and parents in reducing the possible effects of this situation. Multifaceted age-specific and developmentally appropriate strategies must be adopted by healthcare authorities to lessen the negative impact of quarantine on the psychological well-being of children.

Assessing the impact of an evidence- and consensus-based guideline for controlling SARS-CoV-2 transmission in German schools on decision-making processes: a multi-component qualitative analysis

INTRODUCTION

During the COVID-19 pandemic, decision-making on measures to reduce or prevent transmission of SARS-CoV-2 in schools was rendered difficult by a rapidly evolving and uncertain evidence base regarding their effectiveness and unintended consequences. To support decision-makers, an interdisciplinary panel of scientific experts, public health and school authorities as well as those directly affected by school measures, was convened in an unprecedented effort to develop an evidence- and consensus-based public health guideline for German schools. This study sought to assess whether and how this guideline impacted decision-making processes.

METHODS

This study comprised three components: (1) we sent inquiries according to the Freedom of Information Acts of each Federal State to ministries of education, family, and health. (2) We conducted semi-structured interviews with individuals involved in decision-making regarding school measures in two Federal States, and (3) we undertook semi-structured interviews with members of the guideline panel. The content of response letters in component 1 was analysed descriptively; data for components 2 and 3 were analysed using deductive-inductive thematic qualitative content analysis according to Kuckartz.

RESULTS

Responses to the Freedom of Information Act inquiries showed that the guideline was recognised as a relevant source of information by ministries of education in nine out of 16 Federal States and used as a reference to check existing directives for school measures in five Federal States. All participants (20 interviews) emphasised the value of the guideline given its evidence- and consensus-based development process but also noted limitations in its usability and usefulness, e.g., lack of context-specificity. It was consulted by participants who advised policy-makers (5 interviews) alongside other sources of evidence. Overall, perceptions regarding the guideline's impact were mixed.

CONCLUSIONS

Our findings suggest that the guideline was relatively well-known in Federal States' decision-making bodies and that it was considered alongside other forms of evidence in some of these. We suggest that further research to evaluate the impact of public health guidelines on (political) decision-making is warranted. Guideline development processes may need to be adapted to account for the realities of decision-making during public health emergencies and beyond.

Evaluating the Effectiveness of School Closure in COVID-19-Related Syndromes From Community-Based Syndromic Surveillance: Longitudinal Observational Study

BACKGROUND

During the COVID-19 pandemic, a school closure policy was adopted to prevent cluster transmission in schools and subsequent household transmission. However, the effectiveness of school closure is not consistent in studies conducted in different countries.

OBJECTIVE

This study aimed to explore the association between school closure and the daily standardized incidence of COVID-19-related syndromes in an outpatient syndromic surveillance system.

METHODS

We calculated the incidence of COVID-19-related syndromes derived from a community-based syndromic surveillance system between the first week of January and the second or fourth weeks after school closure in 2021 and 2022 in Taipei City, Taiwan. The effect of school closure on the standardized incidence of COVID-19-related syndromes was evaluated by interrupted time series analysis using an autoregressive integrated moving average with a distributed lag function. The exogenous variables were changes in human mobility measured by Google COVID-19 community mobility reports. Furthermore, the models quantified the influence of different age groups and the hierarchy of medical facilities, such as clinics or community hospitals.

RESULTS

School closure was only negatively and significantly associated with the overall standardized incidence of COVID-19-related syndromes in 2021 for 2 weeks after the intervention (coefficient -1.24, 95% CI -2.40 to -0.08). However, in different age groups, school closure had a significantly negative association with the standardized incidence among people aged 13-18 years and ≥65 years for 2 weeks after the intervention in clinics in 2021. In community hospitals, school closure was significantly positively associated with the standardized incidence among people aged 19-24 years in 2021. In 2022, 2 weeks after the intervention, school closure had a significantly negative association with the standardized incidence among people aged 0-6, 7-12, and 19-24 years in community hospitals and aged >45 years in clinics. Furthermore, the standardized incidence was positively associated with movement change toward grocery and pharmacy stores in all age groups in 2022. In addition, movement changes toward residences were significantly positively associated with the standardized incidence among all age groups.

CONCLUSIONS

Overall, school closure effectively suppresses COVID-19-related syndromes in students owing to the reduction of physical contact. In addition, school closure has a spillover effect on elderly people who stay at home.

Impacts of public health and social measures on COVID-19 in Europe: a review and modified Delphi technique

Introduction

The emergence of the COVID-19 pandemic in early 2020 led countries to implement a set of public health and social measures (PHSMs) attempting to contain the spread of the SARS-CoV-2 virus. This study aims to review the existing literature regarding key results of the PHSMs that were implemented, and to identify the PHSMs considered to have most impacted the epidemiological curve of COVID-19 over the last years during different stages of the pandemic.

Methods

The PHSM under study were selected from the Oxford COVID-19 Government Response Tracker (OxCGRT), supplemented by topics presented during the Rapid Exchange Forum (REF) meetings in the scope of the Population Health Information Research Infrastructure (PHIRI) project (H2020). The evidence- based review was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to identify which reviews have already been published about each PHSMs and their results. In addition, two modified Delphi panel surveys were conducted among subject matter experts from 30 European countries to uphold the results found.

Results

There were 3,212 studies retrieved from PubMed, 162 full texts assessed for eligibility and 35 included in this PHSMs summary. The measures with clearest evidence on their positive impact from the evidence-based review include social distancing, hygiene measures, mask measures and testing policies. From the modified Delphi panel, the PHSMs considered most significant in the four periods analyzed were case isolation at home, face coverings, testing policy, and social distancing, respectively.

Discussion

The evidence found has significant implications for both researchers and policymakers. The study of PHSMs' impact on COVID-19 illustrates lessons learned for future pan- and epidemics, serving as a contribution to the health systems resilience discussion. These lessons, drawn from both the available scientific evidence and the perspectives of relevant subject matter experts, should also be considered in educational and preparedness programs and activities in the public health space.

Long COVID as a functional somatic symptom disorder caused by abnormally precise prior expectations during Bayesian perceptual processing: A new hypothesis and implications for pandemic response

This review proposes a model of Long-COVID where the constellation of symptoms are in fact genuinely experienced persistent physical symptoms that are usually functional in nature and therefore potentially reversible, that is, Long-COVID is a somatic symptom disorder. First, we describe what is currently known about Long-COVID in children and adults. Second, we examine reported "Long-Pandemic" effects that create a risk for similar somatic symptoms to develop in non-COVID-19 patients. Third, we describe what was known about somatization and somatic symptom disorder before the COVID-19 pandemic, and suggest that by analogy, Long-COVID may best be conceptualized as one of these disorders, with similar symptoms and predisposing, precipitating, and perpetuating factors. Fourth, we review the phenomenon of mass sociogenic (functional) illness, and the concept of nocebo effects, and suggest that by analogy, Long-COVID is compatible with these descriptions. Fifth, we describe the current theoretical model of the mechanism underlying functional disorders, the Bayesian predictive coding model for perception. This model accounts for moderators that can make symptom inferences functionally inaccurate and therefore can explain how to understand common predisposing, precipitating, and perpetuating factors. Finally, we discuss the implications of this framework for improved public health messaging during a pandemic, with recommendations for the management of Long-COVID symptoms in healthcare systems. We argue that the current public health approach has induced fear of Long-COVID in the population, including from constant messaging about disabling symptoms of Long-COVID and theorizing irreversible tissue damage as the cause of Long-COVID. This has created a self-fulfilling prophecy by inducing the very predisposing, precipitating, and perpetuating factors for the syndrome. Finally, we introduce the term "Pandemic-Response Syndrome" to describe what previously was labeled Long-COVID. This alternative perspective aims to stimulate research and serve as a lesson learned to avoid a repeat performance in the future.

Embracing dynamic public health policy impacts in infectious diseases responses: leveraging implementation science to improve practice

Rationale

The host-pathogen relationship is inherently dynamic and constantly evolving. Applying an implementation science lens to policy evaluation suggests that policy impacts are variable depending upon key implementation outcomes (feasibility, acceptability, appropriateness costs) and conditions and contexts.

COVID-19 case study

Experiences with non-pharmaceutical interventions (NPIs) including masking, testing, and social distancing/business and school closures during the COVID-19 pandemic response highlight the importance of considering public health policy impacts through an implementation science lens of constantly evolving contexts, conditions, evidence, and public perceptions. As implementation outcomes (feasibility, acceptability) changed, the effectiveness of these interventions changed thereby altering public health policy impact. Sustainment of behavioral change may be a key factor determining the duration of effectiveness and ultimate impact of pandemic policy recommendations, particularly for interventions that require ongoing compliance at the level of the individual.

Practical framework for assessing and evaluating pandemic policy

Updating public health policy recommendations as more data and alternative interventions become available is the evidence-based policy approach and grounded in principles of implementation science and dynamic sustainability. Achieving the ideal of real-time policy updates requires improvements in public health data collection and analysis infrastructure and a shift in public health messaging to incorporate uncertainty and the necessity of ongoing changes. In this review, the Dynamic Infectious Diseases Public Health Response Framework is presented as a model with a practical tool for iteratively incorporating implementation outcomes into public health policy design with the aim of sustaining benefits and identifying when policies are no longer functioning as intended and need to be adapted or de-implemented.

Conclusions and implications

Real-time decision making requires sensitivity to conditions on the ground and adaptation of interventions at all levels. When asking about the public health effectiveness and impact of non-pharmaceutical interventions, the focus should be on when, how, and for how long they can achieve public health impact. In the future, rather than focusing on models of public health intervention effectiveness that assume static impacts, policy impacts should be considered as dynamic with ongoing re-evaluation as conditions change to meet the ongoing needs of the ultimate end-user of the intervention: the public.

The Role of Children in Household Transmission of SARS-CoV-2 Across Four Waves of the Pandemic

BACKGROUND

It is important to understand the dynamics of SARS-CoV-2 transmission in close-contact settings such as households. We hypothesized that children would most often acquire SARS-CoV-2 from a symptomatic adult caregiver.

METHODS

This prospective cohort study was conducted from April 2020 to July 2022 in a low-resource, urban settlement in Brazil. We recruited families who brought their children to a public clinic. We collected nasopharyngeal and oral swabs from household members and tracked symptoms and vaccination.

RESULTS

In total, 1256 participants in 298 households were tested for SARS-CoV-2. A total of 4073 RT-PCR tests were run with 893 SARS-CoV-2 positive results (21.9%). SARS-CoV-2 cases were defined as isolated cases (N = 158) or well-defined transmission events (N = 175). The risk of household transmission was lower if the index case was a child (OR: 0.3 [95% CI: 0.16-0.55], P < .001) or was vaccinated (OR: 0.29 [95% CI: 0.1-0.85], P = .024), and higher if the index was symptomatic (OR: 2.53 [95% CI: 1.51-4.26], P < .001). The secondary attack rate for child index cases to child contacts was 0.29, whereas the secondary attack rate for adult index cases to child contacts was 0.47 (P = .08).

CONCLUSIONS

In this community, children were significantly less infectious to their household contacts than adolescents or adults. Most children were infected by a symptomatic adult, usually their mother. There was a double benefit of vaccination as it protected the vaccine from severe illness and prevented onward transmission to household contacts. Our findings may also be valid for similar populations throughout Latin America.

Policies on children and schools during the SARS-CoV-2 pandemic in Western Europe

During the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), mitigation policies for children have been a topic of considerable uncertainty and debate. Although some children have co-morbidities which increase their risk for severe coronavirus disease (COVID-19), and complications such as multisystem inflammatory syndrome and long COVID, most children only get mild COVID-19. On the other hand, consistent evidence shows that mass mitigation measures had enormous adverse impacts on children. A central question can thus be posed: What amount of mitigation should children bear, in response to a disease that is disproportionally affecting older people? In this review, we analyze the distinct child versus adult epidemiology, policies, mitigation trade-offs and outcomes in children in Western Europe. The highly heterogenous European policies applied to children compared to adults did not lead to significant measurable differences in outcomes. Remarkably, the relative epidemiological importance of transmission from school-age children to other age groups remains uncertain, with current evidence suggesting that schools often follow, rather than lead, community transmission. Important learning points for future pandemics are summarized.

SARS-CoV-2 Transmission Risk in the School Environment: a pilot case-ascertained prospective study to inform future school-based surveillance

BACKGROUND

There is no current active or passive disease surveillance programme focused on schools in South Africa. As such the country is missing an opportunity to rapidly and effectively flag and address pathogen outbreaks, for example SARS-CoV-2, in a key closed setting. Furthermore, the role of school transmission in the spread of the SARS-CoV-2 virus within communities is uncertain.  Objective. This pilot study, conducted during March 2022 in Cape Town, aimed to indicate the feasibility of conducting intense active contact-tracing in a school environment prior to a large national study to compare school versus community SARS-CoV-2 transmission risk.  Methods. We conducted a pilot school-level case-ascertained prospective study with a component of enhanced surveillance. Following study initiation, the first learner at a participating school who tested SARS-CoV-2 positive (via Polymerase Chain Reaction (PCR) or a Rapid Antigen Test (RAT)) was invited to join the study as the index case and all their school-based close contacts were followed up telephonically, monitored for symptoms for 14 days, and tested using a PCR if any symptoms were reported.  Results. On 8th March 2022, a student with RAT laboratory-confirmed COVID-19 was identified and they and their guardian consented to participate as the index case. Of the 11 eligible close contacts, six provided consent/assent and completed symptom monitoring calls until the end of the 14-day study period. The Secondary Attack Rate (SAR) was 2/11 (18.18%) of all close contacts who were at risk of infection, 2/4 (50.0%) of all those close contacts who developed symptoms, and 2/4 (50.0%) of all those close contacts who developed symptoms and were tested for SARS-CoV-2. During the same period, the school reported that nine of the 926 learner body tested COVID-19 positive (0.97%). Total hours spent conducting monitoring for 6 learners was 27 hours, with each learner requiring approximately 4.5 hours of contact time during the study period.  Conclusion. This is the first South African school-based COVID-19 transmission study, the results of which can inform national discussions regarding the role of schools and school-based active and passive surveillance in pathogen prevention and control.

Nonpharmaceutical interventions for managing SARS-CoV-2

PURPOSE OF REVIEW

Initial response strategies to the COVID-19 pandemic were heavily reliant on nonpharmaceutical interventions (NPIs), a set of measures implemented to slow or even stop the spread of infection. Here, we reviewed key measures used during the COVID-19 pandemic.

RECENT FINDINGS

Some NPIs were successful in reducing the transmission of SARS-CoV-2. Personal protective measures such as face masks were widely used, and likely had some effect on transmission. The development and production of rapid antigen tests allowed self-diagnosis in the community, informing isolation and quarantine measures. Community-wide measures such as school closures, workplace closures and complete stay-at-home orders were able to reduce contacts and prevent transmission. They were widely used in the pandemic and contributed to reduce transmission in the community; however, there were also negative unintended consequences in the society and economy.

SUMMARY

NPIs slowed the spread of SARS-CoV-2 and are essential for pandemic preparedness and response. Understanding which measures are more effective at reducing transmission with lower costs is imperative.

The corona pandemic and participatory governance: Responding to the vulnerabilities of secondary school students in Europe

Adolescents in secondary schools have limited susceptibility to the SARS-COV-2 virus, but paradoxically are considered to be carrying the highest psychosocial burden during this pandemic. The aim of our European multi-country qualitative research was to investigate the COVID-19 crisis response in secondary schools and the role of national, regional, and local stakeholders in contributing to a participatory governance approach. We carried out 11 months of qualitative fieldwork, which included 90 respondents from the Netherlands, Ireland, and Finland for in-depth interviews and/or group discussions. Participant observation was conducted in four secondary schools to explore the interplay of day-to-day formal and informal practices of crisis governance. Our findings contribute to a better understanding of what efforts were made to facilitate participatory governance and where a bottom-up approach would have served useful in successfully implementing the COVID-19 mitigation strategies. Moreover, we show how these mitigation strategies have led to unintended consequences, such as students' difficulties with isolation and associated mental health problems, and the struggles of socialization when returning to a physical school environment. Our findings highlight the importance of the school environment in the socio-emotional developments of adolescents. We introduce the TAPIC-R model to analyze good governance, advancing the existing TAPIC model with an emphasis on the role of resilience in shaping participatory governance. We argue this is urgently needed during crises to strengthen engagement of the community, including vulnerable groups and achieve positive outcomes within and across policy structures and action domains.

Cross-Theoretical Compliance: An Integrative Compliance Analysis of COVID-19 Mitigation Responses in Israel

To understand the question why people obey or break rules, different approaches have focused on different theories and subsets of variables. The present research develops a cross-theoretical approach that integrates these perspectives. We apply this in a survey of compliance with COVID-19 pandemic mitigation rules in Israel. The data reveal that compliance in this setting was shaped by a combination of variables originating from legitimacy, capacity, and opportunity theories (but not rational choice or social theories). This demonstrates the importance of moving beyond narrow theoretical perspectives of compliance, to a cross-theoretical understanding-in which different theoretical approaches are systematically integrated.

School closures during COVID-19: an overview of systematic reviews

OBJECTIVES

To assess the benefits and drawbacks of school closures and in-school mitigations during the COVID-19 pandemic.

DESIGN

Overview of systematic reviews (SRs).

SEARCH METHODS

We searched six databases and additional resources on 29 July 2022: MEDLINE, Embase, Google Scholar, Cochrane Library, COVID-END inventory of evidence synthesis, and Epistemonikos.

ELIGIBILITY CRITERIA

We selected SRs written in English that answered at least one of four specific questions concerning the efficacy and drawbacks of school closures. Their primary studies were conducted in primary and secondary schools, including pupils aged 5-18. Interventions included school closures or mitigations (such as mask usage) introduced in schools.

DATA COLLECTION AND ANALYSIS

We used AMSTAR 2 to assess confidence in the included SRs, and GRADE was used to assess certainty of evidence. We performed a narrative synthesis of the results, prioritising higher-quality SRs, those which performed GRADE assessments and those with more unique primary studies. We also assessed the overlap between primary studies included in the SRs.

MAIN OUTCOME MEASURES

Our framework for summarising outcome data was guided by the following questions: (1) What is the impact of school closures on COVID-19 transmission, morbidity or mortality in the community? (2) What is the impact of COVID-19 school closures on mental health (eg, anxiety), physical health (eg, obesity, domestic violence, sleep) and learning/achievement of primary and secondary pupils? (3) What is the impact of mitigations in schools on COVID-19 transmission, morbidity or mortality in the community? and (4) What is the impact of COVID-19 mitigations in schools on mental health, physical health and learning/achievement of primary and secondary pupils?

RESULTS

We identified 578 reports, 26 of which were included. One SR was of high confidence, 0 moderate, 10 low and 15 critically low confidence. We identified 132 unique primary studies on the effects of school closures on transmission/morbidity/mortality, 123 on learning, 164 on mental health, 22 on physical health, 16 on sleep, 7 on domestic violence and 69 on effects of in-school mitigations on transmission/morbidity/mortality.Both school closures and in-school mitigations were associated with reduced COVID-19 transmission, morbidity and mortality in the community. School closures were also associated with reduced learning, increased anxiety and increased obesity in pupils. We found no SRs that assessed potential drawbacks of in-school mitigations on pupils. The certainty of evidence according to GRADE was mostly very low.

CONCLUSIONS

School closures during COVID-19 had both positive and negative impacts. We found a large number of SRs and primary studies. However, confidence in the SRs was mostly low to very low, and the certainty of evidence was also mostly very low. We found no SRs assessing the potential drawbacks of in-school mitigations on children, which could be addressed moving forward. This overview provides evidence that could inform policy makers on school closures during future potential waves of COVID-19.

Implementation in an emergency: Qualitative longitudinal research on the experience of implementing Covid-19 prevention in English schools

Implementation studies rarely examine how health interventions are delivered in emergencies. Informed by May's general theory of implementation (GTI), we undertook qualitative longitudinal research to investigate how schools in England implemented Covid-19-prevention measures and how this evolved over the 2020–2021 school year in a rapidly changing epidemiological and policy context. We conducted 74 semi-structured interviews over two time-points with headteachers, teachers, parents and students across eight primary and secondary schools. School leaders rapidly made sense of government guidance despite many challenges. They developed and disseminated prevention plans to staff, parents and students. As defined by GTI, ‘cognitive participation’ and ‘collective action’ to enact handwashing, one-way systems within schools and enhanced cleaning were sustained over time. However, measures such as physical distancing and placing students in separated groups were perceived to conflict with schools' mission to promote student education and wellbeing. Commitment to implement these was initially high during the emergency phase but later fluctuated dependant on perceived risk and local disease epidemiology. They were not considered sustainable in the long term. Adherence to some measures, such as wearing face-coverings, initially considered unworkable, improved as they were routinised. Implementing home-based asymptomatic testing was considered feasible. Formal and informal processes of ‘reflexive monitoring’ by staff informed improvements in intervention workability and implementation. Leaders also developed skills and confidence, deciding on locally appropriate actions, some of which deviated from official guidance. However, over time, accumulating staff burnout and absence eroded school capacity to collectively enact implementation. Qualitative longitudinal research allowed us to understand how implementation in an emergency involved the above emergent processes. GTI was useful in understanding school implementation processes in a pandemic context but may need adaptation to take into account the changing and sometimes contradictory objectives, time-varying factors and feedback loops that can characterise implementation of health interventions in emergencies.

Modeling community COVID-19 transmission risk associated with U.S. universities

The ongoing COVID-19 pandemic is among the worst in recent history, resulting in excess of 520,000,000 cases and 6,200,000 deaths worldwide. The United States (U.S.) has recently surpassed 1,000,000 deaths. Individuals who are elderly and/or immunocompromised are the most susceptible to serious sequelae. Rising sentiment often implicates younger, less-vulnerable populations as primary introducers of COVID-19 to communities, particularly around colleges and universities. Adjusting for more than 32 key socio-demographic, economic, and epidemiologic variables, we (1) implemented regressions to determine the overall community-level, age-adjusted COVID-19 case and mortality rate within each American county, and (2) performed a subgroup analysis among a sample of U.S. colleges and universities to identify any significant preliminary mitigation measures implemented during the fall 2020 semester. From January 1, 2020 through March 31, 2021, a total of 22,385,335 cases and 374,130 deaths were reported to the CDC. Overall, counties with increasing numbers of university enrollment showed significantly lower case rates and marginal decreases in mortality rates. County-level population demographics, and not university level mitigation measures, were the most significant predictor of adjusted COVID-19 case rates. Contrary to common sentiment, our findings demonstrate that counties with high university enrollments may be more adherent to public safety measures and vaccinations, likely contributing to safer communities.

Multiple Concurrent Causal Relationships and Multiple Governance Pathways for Non-Pharmaceutical Intervention Policies in Pandemics: A Fuzzy Set Qualitative Comparative Analysis Based on 102 Countries and Regions

The global outbreak of COVID-19 has been wreaking havoc on all aspects of human societies. In addition to pharmaceutical interventions, non-pharmaceutical intervention policies have been proven to be crucial in slowing down the spread of the virus and reducing the impact of the outbreak on economic development, daily life, and social stability. However, no studies have focused on which non-pharmaceutical intervention policies are more effective; this is the focus of our study. We used data samples from 102 countries and regions around the world and selected seven categories of related policies, including work and school suspensions, assembly restrictions, movement restrictions, home isolation, international population movement restrictions, income subsidies, and testing and screening as the condition variables. A susceptible-exposed-infected-quarantined-recovered (SEIQR) model considering non-pharmaceutical intervention policies and latency with infectiousness was constructed to calculate the epidemic transmission rate as the outcome variable, and a fuzzy set qualitative comparative analysis (fsQCA) method was applied to explore the multiple concurrent causal relationships and multiple governance paths of non-pharmaceutical intervention policies for epidemics from the configuration perspective. We found a total of four non-pharmaceutical intervention policy pathways. Among them, L1 was highly suppressive, L2 was moderately suppressive, and L3 was externally suppressive. The results also showed that individual non-pharmaceutical intervention policy could not effectively suppress the spread of the pandemic. Moreover, three specific non-pharmaceutical intervention policies, including work stoppage and school closure, testing and screening, and economic subsidies, had a universal effect in the policies grouping for effective control of the pandemic transmission.

The next 'pandemic playbook' needs to prioritize the needs of children-and a clear roadmap for opening schools

The national influenza pandemic response plan includes short-term school closures as an infection mitigation measure, based on modeling data regarding the role of pediatric populations and schools as drivers of disease spread. Modeled estimates regarding the role of children and their in-school contacts as drivers of community transmission of endemic respiratory viruses were used in part to justify prolonged school closures throughout the United States. However, disease transmission models extrapolated from endemic pathogens to novel ones may underestimate the degree to which spread is driven by population immunity and overestimate the impact of school closures as a means of reducing child contacts, particularly in the longer-term. These errors, in turn, may have caused incorrect estimations about the potential benefits of closing schools on a society level while simultaneously failing to account for the significant harms of long-term educational disruption. Pandemic response plans need to be updated to include nuances regarding drivers of transmission such as pathogen type, population immunity, and contact patterns, and disease severity in different groups. Expected duration of impact also needs to be considered, recognizing that effectiveness of different interventions, particularly those focused on limiting social interactions, are short-lived. Additionally, future iterations should include risk-benefit assessments. Interventions that are particularly harmful to certain groups, such as school closures are on children, should be de-emphasized and time limited. Finally, pandemic responses should include ongoing and continuous policy re-evaluation and should include a clear plan for de-implementation and de-escalation.

Rapid development of an evidence- and consensus-based guideline for controlling transmission of SARS-CoV-2 in schools during a public health emergency - A process evaluation

Introduction

Different measures to prevent and control the spread of SARS-CoV-2 have been implemented in German schools. Decisions regarding such measures should be informed by evidence regarding their effectiveness, and their unintended consequences for health and society. A multi-stakeholder panel was convened to develop an evidence- and consensus-based guideline for school measures, using the novel WHO-INTEGRATE framework. Developing a guideline to inform decision-making outside of the clinical realm during a public health emergency was unprecedented in Germany. This study aims to identify lessons learnt for similar endeavours by addressing the following research question: What were the strengths and weaknesses of the guideline development process as perceived by the different groups involved?

Methods

Fifteen semi-structured interviews were conducted virtually. We recruited participants aiming to include the perspectives of all groups contributing to the guideline development, including both panel members (scientists, practitioners, school family and observers) and the guideline secretariat. For analysis, we carried out deductive-inductive thematic qualitative text analysis according to Kuckartz, structuring findings using a category system.

Results

Due to time pressure, the guideline secretariat was heavily involved not only in synthesising the evidence but also in developing and drafting recommendations. Participants critically reflected on certain methods-related decisions, including the development of draft recommendations and application of the WHO-INTEGRATE framework by scientists only. The full potential of the framework might not have been harnessed. Participants' understanding of relevant and valid evidence varied, and the available evidence base was limited. Participants represented different types of expertise, notably expertise informed by scientific evidence and expertise grounded in lived experience, influencing their involvement in the guideline development process and discussions during meetings.

Conclusion

Developing an evidence- and consensus-based public health guideline in only three months was challenging, notably because of the involvement of a broad range of stakeholders and the use of a novel Evidence-to-Decision framework, both unprecedented in Germany. Learning from this process with a view to "institutionalising" the development of public health guidelines and refining methods can contribute to more evidence-informed public health decision-making in Germany and beyond, in general and during a public health emergency.

The challenge of estimating the direct and indirect effects of COVID-19 interventions - Toward an integrated economic and epidemiological approach

Decisions on public health measures to contain a pandemic are often based on parameters such as expected disease burden and additional mortality due to the pandemic. Both pandemics and non-pharmaceutical interventions to fight pandemics, however, produce economic, social, and medical costs. The costs are, for example, caused by changes in access to healthcare, social distancing, and restrictions on economic activity. These factors indirectly influence health outcomes in the short- and long-term perspective. In a narrative review based on targeted literature searches, we develop a comprehensive perspective on the concepts available as well as the challenges of estimating the overall disease burden and the direct and indirect effects of COVID-19 interventions from both epidemiological and economic perspectives, particularly during the early part of a pandemic. We review the literature and discuss relevant components that need to be included when estimating the direct and indirect effects of the COVID-19 pandemic. The review presents data sources and different forms of death counts, and discusses empirical findings on direct and indirect effects of the pandemic and interventions on disease burden as well as the distribution of health risks.

Trends in SARS-CoV-2 infection prevalence during England's roadmap out of lockdown, January to July 2021

BACKGROUND

Following rapidly rising COVID-19 case numbers, England entered a national lockdown on 6 January 2021, with staged relaxations of restrictions from 8 March 2021 onwards.

AIM

We characterise how the lockdown and subsequent easing of restrictions affected trends in SARS-CoV-2 infection prevalence.

METHODS

On average, risk of infection is proportional to infection prevalence. The REal-time Assessment of Community Transmission-1 (REACT-1) study is a repeat cross-sectional study of over 98,000 people every round (rounds approximately monthly) that estimates infection prevalence in England. We used Bayesian P-splines to estimate prevalence and the time-varying reproduction number (Rt) nationally, regionally and by age group from round 8 (beginning 6 January 2021) to round 13 (ending 12 July 2021) of REACT-1. As a comparator, a separate segmented-exponential model was used to quantify the impact on Rt of each relaxation of restrictions.

RESULTS

Following an initial plateau of 1.54% until mid-January, infection prevalence decreased until 13 May when it reached a minimum of 0.09%, before increasing until the end of the study to 0.76%. Following the first easing of restrictions, which included schools reopening, the reproduction number Rt increased by 82% (55%, 108%), but then decreased by 61% (82%, 53%) at the second easing of restrictions, which was timed to match the Easter school holidays. Following further relaxations of restrictions, the observed Rt increased steadily, though the increase due to these restrictions being relaxed was offset by the effects of vaccination and also affected by the rapid rise of Delta. There was a high degree of synchrony in the temporal patterns of prevalence between regions and age groups.

CONCLUSION

High-resolution prevalence data fitted to P-splines allowed us to show that the lockdown was effective at reducing risk of infection with school holidays/closures playing a significant part.

Inequalities in the Challenges Affecting Children and their Families during COVID-19 with School Closures and Reopenings: A Qualitative Study

School closure is one of the most debated measures undertaken to contain the spread of the Coronavirus disease (COVID-19) pandemic. The pandemic has devastating health and socio-economic effects and must be contained, but schools play a vital role in present and future well-being, capabilities and health of children. We examine the detrimental consequences of both the closure and reopening of schools, by focusing on inequalities in the challenges affecting children and their families. This paper is grounded on Irish and Italian data from a multi-national longitudinal qualitative interview study. Research participants articulated a variety of issues and challenges that highlight inequalities in access to education during school closures, in the supportiveness of home setting, and in school preparedness to reopen, often mirroring or exacerbating pre-existing inequalities. The reported unequal lived experiences indicate that some harms are actionable, and already suggest some potential harm mitigation strategies. We conclude by advocating for enhanced public consultation to help mitigate the consequences of public dilemmas in general, and to help detect and tackle inadequacies and inequalities for school children through and beyond the pandemic, by learning from the experience of the concerned actors.

Missing science: A scoping study of COVID-19 epidemiological data in the United States

Systematic approaches to epidemiologic data collection are critical for informing pandemic responses, providing information for the targeting and timing of mitigations, for judging the efficacy and efficiency of alternative response strategies, and for conducting real-world impact assessments. Here, we report on a scoping study to assess the completeness of epidemiological data available for COVID-19 pandemic management in the United States, enumerating authoritative US government estimates of parameters of infectious transmission, infection severity, and disease burden and characterizing the extent and scope of US public health affiliated epidemiological investigations published through November 2021. While we found authoritative estimates for most expected transmission and disease severity parameters, some were lacking, and others had significant uncertainties. Moreover, most transmission parameters were not validated domestically or re-assessed over the course of the pandemic. Publicly available disease surveillance measures did grow appreciably in scope and resolution over time; however, their resolution with regards to specific populations and exposure settings remained limited. We identified 283 published epidemiological reports authored by investigators affiliated with U.S. governmental public health entities. Most reported on descriptive studies. Published analytic studies did not appear to fully respond to knowledge gaps or to provide systematic evidence to support, evaluate or tailor community mitigation strategies. The existence of epidemiological data gaps 18 months after the declaration of the COVID-19 pandemic underscores the need for more timely standardization of data collection practices and for anticipatory research priorities and protocols for emerging infectious disease epidemics.

Surveillance, contact tracing and characteristics of SARS-CoV-2 transmission in educational settings in Northern Italy, September 2020 to April 2021

BACKGROUND

The role of school contacts in the spread of the virus and the effectiveness of school closures in controlling the epidemic is still debated. We aimed to quantify the risk of transmission of SARS-CoV-2 in the school setting by type of school, characteristics of the index case and calendar period in the Province of Reggio Emilia (RE), Italy. The secondary aim was to estimate the speed of implementation of contact tracing.

METHODS

A population-based analysis of surveillance data on all COVID-19 cases occurring in RE, Italy, from 1 September 2020, to 4 April 2021, for which a school contact and/or exposure was suspected. An indicator of the delay in contact tracing was calculated as the time elapsed since the index case was determined to be positive and the date on which the swab test for classmates was scheduled (or most were scheduled).

RESULTS

Overall, 30,184 and 13,608 contacts among classmates and teachers/staff, respectively, were identified and were recommended for testing, and 43,214 (98.7%) underwent the test. Secondary transmission occurred in about 40% of the investigated classes, and the overall secondary case attack rate was 4%. This rate was slightly higher when the index case was a teacher but with almost no differences by type of school, and was stable during the study period. Speed of implementation of contact tracing increased during the study period, with the time from index case identification to testing of contacts being reduced from seven to three days. The ability to identify the possible source of infection in the index case also increased.

CONCLUSIONS

Despite the spread of the Alpha variant during the study period in RE, the secondary case attack rate remained stable from school reopening in September 2020 until the beginning of April 2021.

Saliva testing among teachers during the COVID-19 pandemic: Effects on health concerns, well-being, and precautionary behavior

RATIONALE

At the start of 2021, several SARS-CoV-2 cluster outbreaks in schools threatened in-person education and created a fairly chaotic and frightening environment for school personnel. To keep the schools open while preventing COVID-19 outbreaks, intensive diagnostic testing in teachers and school personnel was strongly recommended but missing at the time.

OBJECTIVES

A project was launched in Belgian schools to weekly analyze the morning saliva of school personnel using PCR-testing to detect and prevent COVID-19 positive cases. In this quasi-experimental study, we aimed to examine whether the implementation of this saliva testing project impacted school personnel's pandemic-related health concerns, well-being, and adherence to the health-protective measures, contrasting experimental with control schools.

METHODS

The data were collected during the third wave (Alpha-wave, February-March 2021) of the pandemic. The sample consisted of 435 participants from 34 different schools across Flanders (Belgium) (78.8% female; M age = 43.87 years, range = 21-67) of which 82% participated in the weekly saliva tests (i.e., experimental group) and 18% took part in the control group.

RESULTS

Results from a series of linear mixed regression models showed that saliva testing buffered against an increase in health concerns among tested school personnel but did not affect participants' general well-being. Slight declines in adherence to the health-protective behaviors were observed, yet this was only the case for participants who felt less supported by their school principal. High degrees of principals' support also fostered the sharpest decreases in school staff's pandemic-related health concerns.

CONCLUSIONS

When keeping the schools open in unstable pandemic times, weekly saliva testing is a promising strategy to prevent cluster outbreaks while simultaneously safeguarding health concerns among school personnel. School principals appear to play a critical role in the implementation of saliva testing to secure positive effects.

Epidemiology of SARS-CoV-2 infection among staff and students in a cohort of English primary and secondary schools during 2020-2021

Background

There remains uncertainty about the epidemiology of SARS-CoV-2 among school students and staff and the extent to which non-pharmaceutical-interventions reduce the risk of school settings.

Methods

We conducted an open cohort study in a sample of 59 primary and 97 secondary schools in 15 English local authority areas that were implementing government guidance to schools open during the pandemic. We estimated SARS-CoV-2 infection prevalence among those attending school, antibody prevalence, and antibody negative to positive conversion rates in staff and students over the school year (November 2020-July 2021).

Findings

22,585 staff and students participated. SARS-CoV-2 infection prevalence among those attending school was highest during the first two rounds of testing in the autumn term, ranging from 0.7% (95% CI 0.2, 1.2) among primary staff in November 2020 to 1.6% (95% CI 0.9, 2.3) among secondary staff in December 2020. Antibody conversion rates were highest in the autumn term. Infection patterns were similar between staff and students, and between primary and secondary schools. The prevalence of nucleoprotein antibodies increased over the year and was lower among students than staff. SARS-CoV-2 infection prevalence in the North-West region was lower among secondary students attending school on normal school days than the regional estimate for secondary school-age children.

Interpretation

SARS-CoV-2 infection prevalence in staff and students attending school varied with local community infection rates. Non-pharmaceutical interventions intended to prevent infected individuals attending school may have partially reduced the prevalence of infection among those on the school site.

Funding

UK Department of Health and Social Care.

Model-Based Analysis of SARS-CoV-2 Infections, Hospitalization and Outcome in Germany, the Federal States and Districts

The coronavirus disease 2019 (COVID-19) pandemic challenged many national health care systems, with hospitals reaching capacity limits of intensive care units (ICU). Thus, the estimation of acute local burden of ICUs is critical for appropriate management of health care resources. In this work, we applied non-linear mixed effects modeling to develop an epidemiological SARS-CoV-2 infection model for Germany, with its 16 federal states and 400 districts, that describes infections as well as COVID-19 inpatients, ICU patients with and without mechanical ventilation, recoveries, and fatalities during the first two waves of the pandemic until April 2021. Based on model analyses, covariates influencing the relation between infections and outcomes were explored. Non-pharmaceutical interventions imposed by governments were found to have a major impact on the spreading of SARS-CoV-2. Patient age and sex, the spread of variant B.1.1.7, and the testing strategy (number of tests performed weekly, rate of positive tests) affected the severity and outcome of recorded cases and could reduce the observed unexplained variability between the states. Modeling could reasonably link the discrepancies between fine-grained model simulations of the 400 German districts and the reported number of available ICU beds to coarse-grained COVID-19 patient distribution patterns within German regions.

Evaluation of Non-Pharmacological Measures Implemented in the Management of the COVID-19 Pandemic in Romania

The management of the COVID-19 pandemic in Romania has included the involvement of not only the medical system, but also that of the administrative and social services. All these organizations are working together to lower the impact on the health of the general population, to increase the health system’s response capabilities and even to diminish the negative effects upon the economy due to the epidemic’s length. Therefore, non-pharmacological measures (NPMs) imposed through restrictive measures (administrative, economic and individual) have influenced the evolution of morbidity and mortality. Even from the first months of the pandemic’s progression, researchers have shown the impact of the NPMs’ existence, as there were many studies on all NPMs in conjunction, as well as those targeting specific measures such as school closures. Our study started by establishing a temporal relationship between the non-pharmacological measures found in most countries (wearing a mask, washing hands and physical distancing, limiting economic activities, closing schools, limiting internal and international movement, banning public and private events in closed spaces) and the evolution of the pandemic in Romania. The degree of novelty brought by this study consists of extending the analysis to the pre-existing state of the health system and to the measures meant to increase the resilience of the population, as well as to the measures aimed at reducing the type of risk, and factors that can equally influence the evolution of the number of cases. The results of the statistical analysis show the important effects of certain NPMs (mask mandates, online schooling, decisions regarding imposing or lifting local restrictions) as well as the reduced impact of other measures (hand disinfection, social distancing or the restriction of public and private events). Hence, it can be concluded that during such pandemics, implementing quick, simple measures can prevent the spread of the disease and help fight the contagion in a better manner.

Children in the household and risk of severe COVID-19 during the first three waves of the pandemic: a prospective registry-based cohort study of 1.5 million Swedish men

OBJECTIVE

To investigate whether Swedish men living with children had elevated risk for severe COVID-19 or infection with SARS-CoV-2 during the first three waves of the pandemic.

DESIGN

Prospective registry-based cohort study.

PARTICIPANTS

1 557 061 Swedish men undergoing military conscription between 1968 and 2005 at a mean age of 18.3 (SD 0.73) years.

MAIN OUTCOME MEASURES

Infection with SARS-CoV-2 and hospitalisation due to COVID-19 from March 2020 to September 2021.

RESULTS

There was a protective association between preschool children at home and hospitalisation due to COVID-19 during the first and third waves compared with only older or no children at all, with ORs (95% CIs) 0.63 (0.46 to 0.88) and 0.75 (0.68 to 0.94) respectively. No association was observed for living with children 6-12 years old, but for 13-17 years old, the risk increased. Age in 2020 did not explain these associations. Further adjustment for socioeconomic and health factors did not attenuate the results. Exposure to preschool children also had a protective association with testing positive with SARS-CoV-2, with or without hospitalisation, OR=0.91 (95% CI 0.89 to 0.93), while living with children of other ages was associated with increased odds of infection.

CONCLUSIONS

Cohabiting with preschool children was associated with reduced risk for severe COVID-19. Living with school-age children between 6 and 12 years had no association with severe COVID-19, but sharing the household with teenagers and young adults was associated with elevated risk. Our results are of special interest since preschools and compulsory schools (age 6-15 years) in Sweden did not close in 2020.

Back to school or … back to lockdown? The effects of opening schools on the diffusion of COVID-19 in Italian regions

The opening of schools that coincided with the beginning of fall 2020 and the arrival of the second wave of COVID-19 in continental Europe has fostered significant debate in several countries. Some contributions have suggested that youngsters play a minor role in the spread of the virus, given the specific characteristics of this infection; other scholars have raised concerns about the necessary movement that involves keeping schools open, and the consequent potential spread of the virus. In this study, we focus on the Italian case, an interesting setting in which to test the impact of opening schools on the spread of COVID-19, because of the different dates at which schools have opened in the various Italian provinces, and because of the different rates at which the virus has spread across Italy. Our results suggest that open schools have a positive impact on COVID-19 cases, whose spread occurs between 10 and 14 days after opening. While closing schools or using distance learning have other social and economic consequences, making it necessary for policymakers to adopt a holistic evaluation, it should be taken into account that open schools have an impact on the spread of the pandemic.

Experience with open schools and preschools in periods of high community transmission of COVID-19 in Norway during the academic year of 2020/2021

Background

Schools and preschools have largely remained open in Norway throughout the pandemic, with flexible mitigation measures in place. This contrasts with many other high-income countries that closed schools for long periods of time. Here we describe cases and outbreaks of COVID-19 in schools and preschools during the academic year 2020/2021, to evaluate the strategy of keeping these open with infection prevention control measures in place.

Methods

In this descriptive study, the Norwegian Institute of Public Health initiated systematic surveillance for COVID-19 cases and outbreaks in schools and preschools in October 2020. Data was compiled from the national outbreak alert system VESUV, municipality websites, and media scanning combined with the national emergency preparedness register Beredt C-19. An outbreak was defined as ≥ 2 cases among pupils or staff within 14 days at the same educational setting. Settings were categorized as preschool (1–5-years), primary school (6–12-years), lower secondary school (13–15-years) and upper secondary school (16–18- years). We reported the incidence rate among preschool and school-aged pupils and gave a descriptive overview of outbreaks and included cases per educational setting.

Results

During the whole academic year, a total of 1203 outbreaks in preschools and school settings were identified, out of a total of 8311 preschools and schools nationwide. The incidence of COVID-19 in preschool- and school-aged children and the rates of outbreaks in these settings largely followed the community trend. Most of the outbreaks occurred in primary schools (40%) and preschools (25%). Outbreaks across all settings were mostly small (median 3 cases, range 2 to 72), however, 40 outbreaks (3% of total) included 20 or more cases. The larger outbreaks were predominantly seen in primary schools (43%).

Conclusions

We observed few large outbreaks in open schools and preschools in Norway during the academic year of 2020/2021, also when the Alpha variant was predominant. This illustrates that it is possible to keep schools and preschools open even during periods of high community transmission of COVID-19. Adherence to targeted IPC measures adaptable to the local situation has been essential to keep educational settings open, and thus reduce the total burden on children and adolescents.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13868-5.

Main changes in the "COVID-19 in paediatrics" clinical practice guideline

We present a summary of the main modifications to the “COVID-19 in Paediatrics” clinical practice guideline made from its initial version, published in 2021, and the version published in 2022. The document was developed following the structured steps of evidence-based medicine and applying the GRADE system to synthesize the evidence, assess its quality and, when appropriate, issue graded recommendations (based on the quality of the evidence, values and preferences, the balance between benefits, risks and costs, equity and feasibility). This update also includes the modifications proposed by external reviewers.

We summarised the main modifications in the following sections: epidemiology, clinical features, diagnosis, prevention, treatment and vaccines. In relation to the body of knowledge achieved in the first year of the pandemic, the literature published in the second year contributed additional data, but without substantial modifications in many the areas. The main changes took place in the field of vaccine research. This update was completed in December 2021, coinciding with the emergence of infections by the omicron variant, so the document will need to be updated in the future.

Expresión clínica de la COVID-19 en pediatría de atención primaria: estudio COVIDPAP

Objetivos

En España, las pruebas diagnósticas de COVID-19 en atención primaria estuvieron disponibles desde mayo de 2020. Previamente la mayoría de los estudios describían pacientes hospitalarios: la fiebre y la tos eran los síntomas más frecuentes. Interesaba conocer la expresión clínica de la COVID-19 pediátrica en la comunidad.

Métodos

Estudio descriptivo analítico observacional de casos pediátricos (0-14 años) de 255 pediatras de atención primaria españoles, del 12/5/2020 al 30/4/2021. Los diagnósticos se determinaron por PCR, test rápido de detección de antígeno o serología IgG positiva.

Resultados

Se incluyeron 10.021 niños, 48,4% mujeres, con una edad media de 8,04 ± 4,17 años. Se detectó la infección por búsqueda de contactos (70,9%) o síntomas compatibles (18,8%). El hogar familiar fue la principal fuente de contagio (64,9%), seguido por los colegios (10%) o de origen desconocido (9,9%). No hubo diferencias significativas en la incidencia entre temporadas vacacionales o lectivas. El 43,2% fueron asintomáticos. Los síntomas más frecuentemente encontrados fueron rinorrea en menores de 2 años, fiebre entre 3 y 8 años y cefalea en mayores de 9 años. Se describen exhaustivamente los síntomas y signos observados por edad. Se hospitalizaron a 8 pacientes, uno con un síndrome inflamatorio multisistémico. No hubo fallecimientos.

Conclusiones

La COVID-19 es una enfermedad leve con un gran número de casos asintomáticos, con pocas hospitalizaciones y fallecimientos. El lugar principal de transmisión es el domicilio y el cierre de colegios debería ser el último recurso para controlar la pandemia. No se pudo describir un cuadro clínico característico de la enfermedad.

Schools under mandatory testing can mitigate the spread of SARS-CoV-2

We use event study models based on staggered summer vacations in Germany to estimate the effect of school reopenings after the summer of 2021 on the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Estimations are based on daily counts of confirmed coronavirus infections across all 401 German counties. A central antipandemic measure in German schools included mandatory rapid testing multiple times per week. Our results are consistent with mandatory testing contributing to the containment of the viral spread. We find a short-term increase in infection rates right after summer breaks, indicating the uncovering of otherwise undetected (asymptomatic) cases through the testing. After a period of about 2 wk after school reopenings, the growth of case numbers is smaller in states that reopened schools compared with the control group of states still in summer break. The results show a similar pattern for older age groups as well, arguably as a result of detected clusters through the school testing. This means that under certain conditions, open schools can play a role in containing the spread of the virus. Our results suggest that closing schools as a means to reduce infections may have unintended consequences by giving up surveillance and should be considered only as a last resort.

Lessons learnt: Undertaking rapid reviews on public health and social measures during a global pandemic

Public health and social measures (PHSM) have been central to the COVID‐19 response. Consequently, there has been much pressure on decision‐makers to make evidence‐informed decisions and on researchers to synthesize the evidence regarding these measures. This article describes our experiences, responses and lessons learnt regarding key challenges when planning and conducting rapid reviews of PHSM during the COVID‐19 pandemic. Stakeholder consultations and scoping reviews to obtain an overview of the evidence inform the scope of reviews that are policy‐relevant and feasible. Multiple complementary reviews serve to examine the benefits and harms of PHSM across different populations and contexts. Conceiving reviews of effectiveness as adaptable living reviews helps to respond to evolving evidence needs and an expanding evidence base. An appropriately skilled review team and good planning, coordination and communication ensures smooth and rigorous processes and efficient use of resources. Scientific rigor, the practical implications of PHSM‐related complexity and likely time savings should be carefully weighed in deciding on methodological shortcuts. Making the best possible use of modeling studies represents a particular challenge, and methods should be carefully chosen, piloted and implemented. Our experience raises questions regarding the nature of rapid reviews and regarding how different types of evidence should be considered in making decisions about PHSM during a global pandemic. We highlight the need for readily available protocols for conducting studies on the effectiveness, unintended consequences and implementation of PHSM in a timely manner, as well as the need for rapid review standards tailored to “rapid” versus “emergency” mode reviewing.

COVID-19 clinical features in primary care: COVIDPAP study

OBJECTIVES

In Spain, the tools to diagnose COVID-19 were available in primary care from May 2020. Previously most studies described inpatients or patients in A&E departments, and fever and cough were the most frequent symptoms. This study aims to define the clinical picture of the pediatric COVID-19 in the community.

METHODS

A descriptive and analytical observational study was performed including pediatric cases (0-14years) from 255 pediatricians, proportionally distributed to its population, from primary health centers in Spain, from 12th May 2020 to 30th April 2021. Diagnostics were made by PCR detection of viral RNA, rapid antigen detection test or positive IgG serology.

RESULTS

There were 10,021 positive children included, 48.4% women, mean age 8,04±4.17years. Infection was detected due to contact tracing (70.9%), compatible symptoms (18.8%). Household was the main source of transmission (64.9%), followed by school setting (10%) or unknown (9.9%). We did not find any significant differences in the incidence between holidays and school terms. 43.2% of the children were asymptomatic. Most frequent symptoms are rhinorrhea in <2years, fever in 3-8years and headache in >9years. An exhaustive description of objective and subjective symptoms by age is made. 18 patients were hospitalized, one with multisystem inflammatory syndrome in children. There were no deaths.

CONCLUSIONS

pediatric COVID-19 is a mild disease, with a large number of asymptomatic cases, with very few hospital admissions and deaths. The main setting for transmission is the household, and school closures should be a last resource measure during the COVID-19 pandemic. A specific clinical picture of pediatric COVID-19 was not found.

Unintended consequences of measures implemented in the school setting to contain the COVID-19 pandemic: a scoping review

BACKGROUND

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.

OBJECTIVES

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 METHODS

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.

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.

School Closure Versus Targeted Control Measures for SARS-CoV-2 Infection

OBJECTIVES

To compare effects of school closures with effects of targeted infection prevention and control (IPC) measures in open schools on SARS-CoV-2 infection rates in students.

METHODS

We conducted interrupted time-series analyses to compare trends in infection rates in grades 1-10 in 7 boroughs in Oslo, Norway, between February 15 and April 18, 2021. All schools at all levels had implemented strict IPC measures. While grades 1-4 attended school throughout the study period, school closures were implemented for grades 5-10 from March 17. We obtained individual level data from nationwide registries.

RESULTS

A total of 616, 452, and 446 students in grades 1-4, 5-7 and 8-10, respectively, were registered with a positive SARS-CoV-2 test during the study period, when the α-variant dominated. A statistically significant reduction in postintervention trends was observed for grades 1-4 (coefficient -1.26; 95% confidence interval (CI), -2.44 to -0.09). We did not observe any statistically significant between-group differences in postintervention trends between grades 1-4 and 5-7 (coefficient 0.66; 95% CI, -1.25 to 2.58) nor between grades 1-4 and 8-10 (coefficient -0.63; 95% CI, -2.30 to 1.04). Findings indicate that keeping schools open with strict IPC measures was equally effective as school closures on reducing student infection rates.

CONCLUSIONS

School closure was not more effective than targeted IPC measures in open schools in reducing student infection rates. Our findings suggest that keeping schools open with appropriate IPC measures should be preferred over school closures, considering the negative consequences closures have on students.

School Closures During Social Lockdown and Mental Health, Health Behaviors, and Well-being Among Children and Adolescents During the First COVID-19 Wave: A Systematic Review

IMPORTANCE

School closures as part of broader social lockdown measures during the COVID-19 pandemic may be associated with the health and well-being of children and adolescents.

OBJECTIVE

To review published reports on the association of school closures during broader social lockdown with mental health, health behaviors, and well-being in children and adolescents aged 0 to 19 years, excluding associations with transmission of infection.

EVIDENCE REVIEW

Eleven databases were searched from inception to September 2020, and machine learning was applied for screening articles. A total of 16 817 records were screened, 151 were reviewed in full text, and 36 studies were included. Quality assessment was tailored to study type. A narrative synthesis of results was undertaken because data did not allow meta-analysis.

FINDINGS

A total of 36 studies from 11 countries were identified, involving a total of 79 781 children and adolescents and 18 028 parents, which occurred during the first wave of the COVID-19 pandemic (February to July 2020). All evaluated school closure as part of broader social lockdown during the first COVID-19 wave, and the duration of school closure ranged from 1 week to 3 months. Of those, 9 (25%) were longitudinal pre-post studies, 5 (14%) were cohort, 21 (58%) were cross-sectional, and 1 (3%) was a modeling study. Thirteen studies (36%) were high quality, 17 (47%) were medium quality, and 6 (17%) were low quality. Twenty-three studies (64%) were published, 8 (22%) were online reports, and 5 (14%) were preprints. Twenty-five studies (69%) concerning mental health identified associations across emotional, behavioral, and restlessness/inattention problems; 18% to 60% of children and adolescents scored above risk thresholds for distress, particularly anxiety and depressive symptoms, and 2 studies reported no significant association with suicide. Three studies reported that child protection referrals were lower than expected number of referrals originating in schools. Three studies suggested higher screen time usage, 2 studies reported greater social media use, and 6 studies reported lower physical activity. Studies on sleep (10 studies) and diet (5 studies) provided inconclusive evidence on harms.

CONCLUSIONS AND RELEVANCE

In this narrative synthesis of reports from the first wave of the COVID-19 pandemic, studies of short-term school closures as part of social lockdown measures reported adverse mental health symptoms and health behaviors among children and adolescents. Associations between school closure and health outcomes and behaviors could not be separated from broader lockdown measures.

Expert Consensus on COVID-19 Vaccination in Korean Adolescents: A Modified Delphi Survey

The effectiveness of coronavirus disease 2019 (COVID-19) vaccines had been shown in many studies in adult population, however, the real-world evidence in the childhood population was scarce. We aimed to organize the collective expert's opinions on adolescent vaccination against COVID-19 in Korea, therefore to guide the vaccination policy in the setting of available evidence. The Delphi panels responded that adolescents were greatly impacted by the quarantine measures, and COVID-19 is an important health problem for adolescents. Panels responded that in general, the benefits of the COVID-19 vaccine overweigh the potential risks in Korean adolescents. Continuing monitoring of available data is needed to provide the best vaccination practices in adolescents guided by the updated evidence.

A new threshold reveals the uncertainty about the effect of school opening on diffusion of Covid-19

Studies on the effects of school openings or closures during the Covid-19 pandemic seem to reach contrasting conclusions even in similar contexts. We aim at clarifying this controversy. A mathematical analysis of compartmental models with subpopulations has been conducted, starting from the SIR model, and progressively adding features modeling outbreaks or upsurge of variants, lockdowns, and vaccinations. We find that in all cases, the in-school transmission rates only affect the overall course of the pandemic above a certain context dependent threshold. We provide rigorous proofs and computations of the thresdhold through linearization. We then confirm our theoretical findings through simulations and the review of data-driven studies that exhibit an often unnoticed phase transition. Specific implications are: awareness about the threshold could inform choice of data collection, analysis and release, such as in-school transmission rates, and clarify the reason for divergent conclusions in similar studies; schools may remain open at any stage of the Covid-19 pandemic, including variants upsurge, given suitable containment rules; these rules would be extremely strict and hardly sustainable if only adults are vaccinated, making a compelling argument for vaccinating children whenever possible.