Department of Economics, Stockholm University, 106 91 Stockholm, Sweden.
Department of Economics, Uppsala University, 751 20 Uppsala, Sweden.
Proc Natl Acad Sci U S A. 2021 Mar 2;118(9). doi: 10.1073/pnas.2020834118.
To reduce the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), most countries closed schools, despite uncertainty if school closures are an effective containment measure. At the onset of the pandemic, Swedish upper-secondary schools moved to online instruction, while lower-secondary schools remained open. This allows for a comparison of parents and teachers differently exposed to open and closed schools, but otherwise facing similar conditions. Leveraging rich Swedish register data, we connect all students and teachers in Sweden to their families and study the impact of moving to online instruction on the incidence of SARS-CoV-2 and COVID-19. We find that, among parents, exposure to open rather than closed schools resulted in a small increase in PCR-confirmed infections (odds ratio [OR] 1.17; 95% CI [CI95] 1.03 to 1.32). Among lower-secondary teachers, the infection rate doubled relative to upper-secondary teachers (OR 2.01; CI95 1.52 to 2.67). This spilled over to the partners of lower-secondary teachers, who had a higher infection rate than their upper-secondary counterparts (OR 1.29; CI95 1.00 to 1.67). When analyzing COVID-19 diagnoses from healthcare visits and the incidence of severe health outcomes, results are similar for teachers, but weaker for parents and teachers' partners. The results for parents indicate that keeping lower-secondary schools open had minor consequences for the overall transmission of SARS-CoV-2 in society. The results for teachers suggest that measures to protect teachers could be considered.
为了减少严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）的传播，大多数国家关闭了学校，尽管不确定学校关闭是否是一种有效的控制措施。在大流行开始时，瑞典的高中转为在线教学，而初中仍然开放。这使得我们可以比较接触开放和关闭学校的家长和教师，除了学校环境不同外，其他条件基本相同。利用丰富的瑞典登记数据，我们将瑞典所有的学生和教师与其家庭联系起来，研究转向在线教学对 SARS-CoV-2 和 COVID-19 发病率的影响。我们发现，在家长中，接触开放而不是关闭的学校会导致 PCR 确诊感染的小幅度增加（优势比[OR]1.17；95%置信区间[CI95]1.03 至 1.32）。与高中教师相比，初中教师的感染率增加了一倍（OR 2.01；CI95 1.52 至 2.67）。这也蔓延到了初中教师的伴侣身上，他们的感染率高于高中教师（OR 1.29；CI95 1.00 至 1.67）。当分析来自医疗保健就诊的 COVID-19 诊断和严重健康结果的发病率时，结果对教师而言相似，但对家长和教师的伴侣而言较弱。对家长的结果表明，保持初中开放对 SARS-CoV-2 在社会中的总体传播影响不大。对教师的结果表明，可以考虑采取措施保护教师。
