Association Between Statewide School Closure and COVID-19 Incidence and Mortality in the US

Abstract

In the US, states enacted nonpharmaceutical interventions, including school closure, to reduce the spread of coronavirus disease 2019 (COVID-19). All 50 states closed schools in March 2020 despite uncertainty if school closure would be effective. OBJECTIVE To determine if school closure and its timing were associated with decreased COVID-19 incidence and mortality. DESIGN, SETTING, AND PARTICIPANTS US population-based observational study conducted between March 9, 2020, and May 7, 2020, using interrupted time series analyses incorporating a lag period to allow for potential policy-associated changes to occur. To isolate the association of school closure with outcomes, state-level nonpharmaceutical interventions and attributes were included in negative binomial regression models. States were examined in quartiles based on state-level COVID-19 cumulative incidence per 100 000 residents at the time of school closure. Models were used to derive the estimated absolute differences between schools that closed and schools that remained open as well as the number of cases and deaths if states had closed schools when the cumulative incidence of COVID-19 was in the lowest quartile compared with the highest quartile. EXPOSURES Closure of primary and secondary schools. MAIN OUTCOMES AND MEASURES COVID-19 daily incidence and mortality per 100 000 residents. RESULTS COVID-19 cumulative incidence in states at the time of school closure ranged from 0 to 14.75 cases per 100 000 population. School closure was associated with a significant decline in the incidence of COVID-19 (adjusted relative change per week, −62% [95% CI, −71% to −49%]) and mortality (adjusted relative change per week, −58% [95% CI, −68% to −46%]). Both of these associations were largest in states with low cumulative incidence of COVID-19 at the time of school closure. For example, states with the lowest incidence of COVID-19 had a −72% (95% CI, −79% to −62%) relative change in incidence compared with −49% (95% CI, −62% to −33%) for those states with the highest cumulative incidence. In a model derived from this analysis, it was estimated that closing schools when the cumulative incidence of COVID-19 was in the lowest quartile compared with the highest quartile was associated with 128.7 fewer cases per 100 000 population over 26 days and with 1.5 fewer deaths per 100 000 population over 16 days. CONCLUSIONS AND RELEVANCE Between March 9, 2020, and May 7, 2020, school closure in the US was temporally associated with decreased COVID-19 incidence and mortality; states that closed schools earlier, when cumulative incidence of COVID-19 was low, had the largest relative reduction in incidence and mortality. However, it remains possible that some of the reduction may have been related to other concurrent nonpharmaceutical interventions.

State-level variation of initial COVID-19 dynamics in the United States

“…The overall doubling time (first 21 days of the epidemic) in each state was also correlated with demographic parameters. However, in line with past work [28,40,41], we show early https://doi.org/10.1371/journal.pone.0240648.g002…”

“…We did not examine the doubling time after 21 days as some states were already recorded a decrease in the daily number of cases per day at that point (S2 Fig). The early doubling time should not be strongly correlated with government interventions as these were often implemented late and there is a delay in which effects from government actions are detectable [28].…”

Social and emotional loneliness among college students during the COVID-19 pandemic: the predictive role of coping behaviours, social support, and personal resilience

“…Tull et al (2020) suggested that measures such as home con nement, social distancing, and quarantine to control infection greatly contribute to a sense of loneliness among young people as they restrict them from socialising with their peers. In addition, closure of schools could partly play a role in the development of loneliness among students as school routines and activities were identi ed as essential coping mechanisms, especially for young people (Auger et al, 2020).…”

The Role of Children in SARS-CoV-2 Transmission

“…These associations were largest in states with low case numbers at the time of school closure. 30 In a prospective cohort study of 144 countries, states or provinces between March 7 and March 27, 2020, Jüni et al found a 37% reduction in epidemic growth associated with school closures (95% confidence interval 22 to 48%). 31 The other public health interventions studied were restrictions of mass gatherings and social distancing measures.…”

“…31 In a subsequent retrospective study in 149 countries or regions between January 1 and May 30, 2020, Islam et al found school closures, in combination with other types of public health interventions, to be associated with an average reduction in incidence of 13% (95% confidence interval 11 to 15%). 32 All three studies on school closures [30][31][32] were observational, ecological studies. Causality can therefore not be established.…”