Effects of K-12 School District Nonpharmaceutical Interventions on Community-Level Prevalence of Acute Respiratory Infection During the COVID-19 Pandemic.

BACKGROUND

Responding to the COVID-19 pandemic, kindergarten through 12th grade schools implemented nonpharmaceutical interventions (NPIs). The effects of school-based NPIs on broader community levels of acute respiratory infection (ARI) have not been defined. We utilized an existing longitudinal cohort of households reporting weekly ARI cases to evaluate the effects of evolving school districtwide NPIs on ARI activity at eight transition points from December 2019 through October 2022.

METHODS

Household ARI data were reported through the GReat Oregon Child Absenteeism due to Respiratory Disease Study (ORCHARDS) Vaccine Effectiveness Study-a prospective cohort study based in the Oregon School District (OSD) (GROVES). Participating GROVES families completed weekly online surveys with respiratory illness updates. Mixed effects logistic regression was used to examine the association between eight school-related transition events during the COVID-19 pandemic and changes in the trajectory of ARI risk for GROVES family members, while accounting for family clusters. Transition events were assessed using a ±4-week window of community data.

RESULTS

Opening schools with maximal NPIs (mandated masking and physical distancing, with hybrid education) was not associated with increased community ARI activity. The four transition events associated with significant ARI risk trajectory increases included summer breaks (June 2020, p = 0.001; June 2021, p = 0.002), and the start of school with mandatory masking only (September 2021, p < 0.001) or without NPIs (September 2022, p < 0.001).

CONCLUSIONS

School-based NPI implementation was associated with reduced risks for community ARI activity. Enhanced surveillance platforms such as the weekly online surveys used in this study are valuable tools for better understanding and monitoring SARS-CoV-2 and respiratory virus transmission in schools and surrounding communities.