Implications for the academic and interpersonal development of children and adolescents underpin a global political consensus to maintain in-classroom teaching during the ongoing COVID-19 pandemic. In support of this aim, the WHO and UNICEF have called for schools around the globe to be made safer from the risk of COVID-19 transmission. Detailed guidance is needed on how this goal can be successfully implemented in a wide variety of educational settings in order to effectively mitigate impacts on the health of students, staff, their families, and society. This review provides a comprehensive synthesis of current scientific evidence and emerging standards in relation to the use of layered prevention strategies (involving masks, distancing, and ventilation), setting out the basis for their implementation in the school environment. In the presence of increasingly infectious SARS-Cov-2 variants, in-classroom teaching can only be safely maintained through a layered strategy combining multiple protective measures. The precise measures that are needed at any point in time depend upon a number of dynamic factors, including the specific threat-level posed by the circulating variant, the level of community infection, and the political acceptability of the resultant risk. By consistently implementing appropriate prophylaxis measures, evidence shows that the risk of infection from in-classroom teaching can be dramatically reduced. Current studies indicate that wearing high-quality masks and regular testing are amongst the most important measures in preventing infection transmission; whilst effective natural and mechanical ventilation systems have been shown to reduce infection risks in classrooms by over 80%.

中文翻译：

---

学校 COVID-19 感染预防的多层次策略：口罩、距离和通风的证据回顾

对儿童和青少年学业和人际关系发展的影响巩固了全球政治共识，即在持续的 COVID-19 大流行期间维持课堂教学。为支持这一目标，世界卫生组织和联合国儿童基金会呼吁全球各地的学校更加安全，免受 COVID-19 传播的风险。需要详细指导如何在各种教育环境中成功实施这一目标，以有效减轻对学生、教职员工、他们的家庭和社会健康的影响。本综述全面综合了与使用分层预防策略（包括口罩、保持距离和通风）相关的当前科学证据和新兴标准，为在学校环境中实施这些策略奠定了基础。多重保护措施相结合的分层策略。在任何时间点所需的精确措施取决于许多动态因素，包括传播变体造成的具体威胁级别、社区感染级别以及由此产生的风险的政治可接受性。通过始终如一地实施适当的预防措施，证据表明课堂教学中感染的风险可以大大降低。目前的研究表明，佩戴优质口罩和定期检测是预防感染传播的最重要措施之一；同时，有效的自然和机械通风系统已被证明可以将教室内的感染风险降低 80% 以上。