1. Overview of intervention categories.

Broad intervention category	Included interventions
Measures reducing the opportunity for contacts	Phased reopening of schools Reduced cohort size Staggered start/end time Alternating attendance Only allowing schooling in person for certain grades/students
Measures making contacts safer	Face masks Handwashing interventions Cleaning interventions Modifying activities in the school setting Ventilation interventions Combined measures to make contacts safer
Surveillance and response measures	Mass testing and isolation measures Symptom‐based screening and quarantine measures
Multicomponent measures	Multiple measures including: reduced cohort size, face masks, handwashing interventions, modifying activities in the school setting, cleaning, testing, and quarantine