Littlecott Hannah, Krishnaratne Shari, Burns Jacob, Rehfuess Eva, Sell Kerstin, Klinger Carmen, Strahwald Brigitte, Movsisyan Ani, Metzendorf Maria-Inti, Schoenweger Petra, Voss Stephan, Coenen Michaela, Müller-Eberstein Roxana, Pfadenhauer Lisa M
Institute for Medical Information Processing, Biometry and Epidemiology - IBE, Chair of Public Health and Health Services Research, LMU Munich, Munich, Germany.
Pettenkofer School of Public Health, Munich, Germany.
Cochrane Database Syst Rev. 2024 May 2;5(5):CD015029. doi: 10.1002/14651858.CD015029.pub2.
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.
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.
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.
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.
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.
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.
截至2023年8月，全球已记录超过7.67亿例2019冠状病毒病（COVID-19）病例，690万人死于COVID-19。学校实施了多项公共卫生和社会措施，以遏制严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的传播并防止病毒进一步传播。我们基于之前Cochrane系统评价的方法，收集了有关学校措施限制SARS-CoV-2传播有效性的当前实证证据。
对学校在COVID-19大流行期间实施的措施有效性的证据进行更新评估，以确保学校安全开放。
我们于2022年2月18日检索了Cochrane COVID-19研究注册库、教育资源信息中心、世界卫生组织（WHO）COVID-19冠状病毒病全球文献数据库以及美国退伍军人事务部证据综合计划COVID-19证据综述。
符合条件的研究聚焦于在学校环境中实施的遏制COVID-19大流行的措施，涉及学生（4至18岁）或与学校相关的人员，或两者皆有。我们将报告干预效果定量测量的研究，以及评估监测措施性能的研究，根据设计和处理关键混杂因素的方法，分为“主要”或“支持性”研究。我们关注与传播相关的结果以及预期或非预期的后果。
两位综述作者筛选标题、摘要和全文。我们为支持性研究提取了最少的数据。对于主要研究，一位综述作者提取了全面的数据并评估偏倚风险，另一位作者进行核对。我们对每个干预-对照-结果类别（证据体）的研究结果进行叙述性综合。两位综述作者评估证据的确定性。
15项主要研究包括减少接触的措施（4项研究）、使接触更安全的措施（7项研究）、监测和应对措施（6项研究；1项评估传播结果，5项评估监测措施的性能）以及多组分措施（1项研究）。这些主要研究评估了学校人群（12项）、一般人群（2项）以及与在校儿童同住的成年人（1项）的结果。研究环境包括K-12（幼儿园至12年级；9项研究）、中学（3项研究）和K-8（幼儿园至8年级；1项研究）学校。两项研究未明确报告研究环境。研究测量了与传播相关的结果（10项）、监测措施的性能（5项）以及预期和非预期的后果（4项）。15项主要研究基于世界卫生组织美洲区域（12项）和欧洲区域（3项）。对照措施包括强度较高与较低的措施、单一与多组分措施以及措施与无措施。我们将结果整理成相关的证据体，即与相同“干预-对照-结果”类别相关的研究组。在所有证据体中，证据的确定性评级限制了我们对研究结果的信心。当我们将一种效应描述为“有益”时，效应点估计的方向有利于干预措施；“有害”效应则不利于干预措施，“无”效应表示无论哪种方式均无效果。减少接触的措施（4项研究）我们将研究分为21个证据体：中等确定性证据（10个证据体）、低确定性证据（3个证据体）或极低确定性证据（8个证据体）。对于一般人群，远程教学与面对面或混合教学相比，对传播的有益效果的证据确定性为极低到中等。对于学生和教职员工，当更多学生参与远程教学时，大多观察到有害影响。中等确定性证据表明，对于一般人群，远程教学与面对面教学相比，可能对死亡无影响，对住院有有益影响，但远程教学与混合教学相比无影响。混合教学（面对面和远程教学相结合）的效果不一。极低确定性证据表明，关闭操场和食堂可能对与在校学生同住的成年人的感染风险有有害影响，保留同一位教师无影响，取消课外活动、让相同的学生在一起以及限制家长和照顾者进入可能有有益影响。使接触更安全的措施（7项研究）我们将研究分为八个证据体：中等确定性证据（5个证据体）和低确定性证据（3个证据体）。低确定性证据表明，强制佩戴口罩可能对与传播相关的结果有有益影响。中等确定性证据表明，全面强制佩戴口罩可能比部分或不强制佩戴更有益。关于物理距离对教职员工和学生感染风险的有益影响的证据不一。中等确定性证据表明，通风措施可能减少教职员工和学生中的病例。一项研究（极低确定性证据）发现，不共享用品和增加课桌空间可能对与在校学生同住的成年人的感染风险有有益影响，但表明课桌防护板可能有有害影响。监测和应对措施（6项研究）我们将研究分为七个证据体：中等确定性证据（3个证据体）、低确定性证据（1个证据体）和极低确定性证据（3个证据体）。用每日检测策略替代或减少隔离可能有助于减少缺课天数，并降低无症状学校接触者检测呈阳性的比例（中等确定性证据）。对于评估监测措施性能的研究，快速抗原检测检测到的病例比例为28.6%至95.8%，阳性预测值为24.0%至100.0%（极低确定性证据）。阳性病例的接触者可能没有病毒进一步传播（中等确定性证据），用检测替代或缩短隔离可能减少缺课天数（低确定性证据）。多组分措施（1项研究）综合多种措施可能会降低与学生同住的成年人的感染风险（极低确定性证据）。
一系列措施可能对与传播相关的结果、医疗保健利用和学校出勤产生有益影响。我们对当前研究结果的确定性评级高于原始综述。需要在更广泛的背景下对学校控制SARS-CoV-2的措施进行进一步的高质量研究，以便更基于证据地理解如何在COVID-19或类似的公共卫生紧急情况期间安全地保持学校开放。
