Key Safety Layers

Making Schools the Safest Places in the Community

Swiss cheese model of preventing COVID-19 transmission

Image credit: UCSF CARES, Naomi Bardach and Safe Schools for All

* As of April 2, masking is strongly recommended but not required

To keep schools safe, we rely on a "Swiss cheese" model. Each layer has holes, but when several of them overlap, it makes COVID-19 transmission much more difficult. The layers are:

  • All 5+ in school are vaccinated
  • Testing and staying home when feeling sick
  • Wearing masks indoors and hand hygiene
  • Improve indoor air quality and stay outdoors when possible

This page was last updated on August 4, 2022