Fig. 1: Timeline of Key COVID-19 mitigation policy change milestones in Massachusetts elementary and secondary schools, 2021ā2022 academic Year.

Key infection mitigation measure policies in Massachusetts elementary and secondary schools throughout the 2021ā2022 academic year. Dates and dotted lines indicate date of policy or program implementation or change. Total duration of the policy is indicated with red arrows. Dominant variant is indicated with green arrows.