School closures and respiratory infections transmission and mortality: evidence from school holidays in Poland

Am J Epidemiol. 2025 Oct 7;194(10):2853-2860. doi: 10.1093/aje/kwae453.

Abstract

This study examines the impact of temporary school closures on influenza transmission and respiratory mortality, leveraging a natural experiment from winter break timings in Polish schools. Using causal inference methods on 12 years of influenza-like illness (ILI) data and 2 decades of respiratory death records, the analysis shows significant reductions in ILI incidence within 4 weeks after closures in an average season: 75% among school-aged children, 55% in adults, 26% in preschool children, and 31% in the elderly, compared to prevacation averages. Notably, a 7% decrease in respiratory mortality was observed among the elderly, highlighting school closures as an effective public health intervention for reducing influenza spread and mortality among high-risk groups.

Keywords: influenza; respiratory mortality; school closure.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Female
  • Holidays*
  • Humans
  • Incidence
  • Influenza, Human* / epidemiology
  • Influenza, Human* / mortality
  • Influenza, Human* / prevention & control
  • Influenza, Human* / transmission
  • Male
  • Middle Aged
  • Poland / epidemiology
  • Respiratory Tract Infections* / epidemiology
  • Respiratory Tract Infections* / mortality
  • Respiratory Tract Infections* / transmission
  • Schools* / organization & administration
  • Seasons
  • Young Adult