The effects of school closures on SARS-CoV-2 among parents and teachers

Abstract

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.

Keywords: COVID-19; SARS-CoV-2; school closures; social distancing.

Fig. 1.

COVID-19 deaths and intensive care unit (ICU) admissions. The 7-day averages (avg) of deaths and ICU admissions. Solid vertical lines mark the start of school closure and the end of the period of analysis. Data are from the Public Health Agency of Sweden (18).

Fig. 2.

SARS-CoV-2 ORs for parents by school year of the youngest child in the household. ORs are estimated using logistic regression. The reference category is school year 10, and CI95 values are indicated.

Fig. 3.

SARS-CoV-2 across occupations. Circle size corresponds to the number of employees in each occupation. Incidence (cases per 1,000) of detected SARS-CoV-2 by three-digit occupational codes (SSYK 2012) until June 15, 2020, is shown. Ages are 25–65, and only occupations with at least 1,000 employees are reported. Values for the upper- and lower-secondary teachers (as well as lower- and upper-primary teachers in gray) from the Teacher Register in our sample are indicated in black.