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.

WHAT'S KNOWN ON THIS SUBJECT: Various low-risk criteria have been developed to guide management of the febrile young infant (,90 days), but they differ in age criteria, recommendations, and implementation. Therefore, variation in care is likely but has not been previously studied. WHAT THIS STUDY ADDS:There is wide variation in testing, treatment, and overall resource utilization in management of the febrile young infant across all 3 age groups: #28, 29 to 56, and 57 to 89 days. There may be opportunities to improve care variation without compromising outcomes. abstract BACKGROUND AND OBJECTIVES: Variation in patient care or outcomes may indicate an opportunity to improve quality of care. We evaluated the variation in testing, treatment, hospitalization rates, and outcomes of febrile young infants in US pediatric emergency departments (EDs). METHODS:Retrospective cohort study of infants ,90 days of age with a diagnosis code of fever who were evaluated in 1 of 37 pediatric EDs between July 1, 2011 and June 30, 2013. We assessed patient-and hospital-level variation in testing, treatment, and disposition for patients in 3 distinct age groups: #28, 29 to 56, and 57 to 89 days. We also compared interhospital variation for 3-day revisits and revisits resulting in hospitalization. RESULTS:We identified 35 070 ED visits that met inclusion criteria. The proportion of patients who underwent comprehensive evaluation, defined as urine, serum, and cerebrospinal fluid testing, decreased with increasing patient age: 72.0% (95% confidence interval [CI], 71.0-73.0) of neonates #28 days, 49.0% (95% CI, 48.2-49.8) of infants 29 to 56 days, and 13.1% (95% CI, 12.5-13.6) of infants 57 to 89 days. Significant interhospital variation was demonstrated in testing, treatment, and hospitalization rates overall and across all 3 age groups, with little interhospital variation in outcomes. Hospitalization rate in the overall cohort did not correlate with 3-day revisits (R 2 = 0.10, P = .06) or revisits resulting in hospitalization (R 2 = 0.08, P = .09).

Background Differences among febrile infant institutional clinical practice guidelines (CPGs) may contribute to practice variation and increase healthcare costs. Objective Determine the association between pediatric emergency department (ED) CPGs and laboratory testing, hospitalization, ceftriaxone use, and costs in febrile infants. Design Retrospective cross-sectional study in 2013. Setting Thirty-three hospitals in the Pediatric Health Information System. Patients Infants ≤ 56 days with a diagnosis of fever. Exposures The presence and content of ED-based febrile infant CPGs assessed by electronic survey. Measurements Using generalized estimating equations, we evaluated the association between CPG recommendations and rates of urine, blood, cerebrospinal fluid (CSF) testing, hospitalization, and ceftriaxone use at ED discharge in two age groups: ≤ 28 days and 29-56 days. We also assessed CPG impact on healthcare costs. Results We included 9,377 ED visits; 21 of 33 EDs (63.6%) had a CPG. For neonates ≤ 28 days, CPG recommendations did not vary and were not associated with differences in testing, hospitalization, or costs. Among infants 29-56 days, CPG recommendations for CSF testing and ceftriaxone use varied. CSF testing occurred less often at EDs with CPGs recommending limited testing compared to hospitals without CPGs (aOR 0.5, 95% CI: 0.3-0.8). Ceftriaxone use at ED discharge varied significantly based on CPG recommendations. Costs were higher for admitted and discharged infants 29-56 days at hospitals with CPGs. Conclusions CPG recommendations for febrile infants 29-56 days vary across institutions for CSF testing and ceftriaxone use, correlating with observed practice variation. CPGs were not associated with lower healthcare costs.