Reopening schools is an urgent priority as the COVID-19 pandemic drags on. To explore the risks associated with returning to in-person learning and the value of mitigation measures, we developed stochastic, network-based models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission in primary and secondary schools. We find that a number of mitigation measures, alone or in concert, may reduce risk to acceptable levels. Student cohorting, in which students are divided into two separate populations that attend in-person classes on alternating schedules, can reduce both the likelihood and the size of outbreaks. Proactive testing of teachers and staff can help catch introductions early, before they spread widely through the school. In secondary schools, where the students are more susceptible to infection and have different patterns of social interaction, control is more difficult. Especially in these settings, planners should also consider testing students once or twice weekly. Vaccinating teachers and staff protects these individuals and may have a protective effect on students as well. Other mitigations, including mask wearing, social distancing, and increased ventilation, remain a crucial component of any reopening plan.

随着 COVID-19 大流行的持续，重新开放学校是当务之急。为了探索恢复面对面学习的相关风险以及缓解措施的价值，我们开发了基于网络的严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 在中小学传播的随机模型。我们发现，一些缓解措施，单独或协同作用，可以将风险降低到可接受的水平。学生分组将学生分为两个不同的群体，轮流参加面对面的课程，可以减少疫情爆发的可能性和规模。对教师和工作人员进行主动测试可以帮助尽早发现新情况，避免它们在学校广泛传播。在中学，学生更容易受到感染，并且社交互动模式不同，控制更加困难。特别是在这些环境中，规划者还应该考虑每周对学生进行一次或两次测试。为教师和工作人员接种疫苗可以保护这些人，也可能对学生产生保护作用。其他缓解措施，包括戴口罩、保持社交距离和加强通风，仍然是任何重新开放计划的重要组成部分。