The graph is an event-study figure titled "College Vaccination Mandates and COVID-19 Deaths."
The chart plots estimates of the difference in the COVID-19 death rate between counties with and without a college vaccine mandate, relative to two weeks before the semester begins.
The y-axis ranges from -1.4 to 0.4 deaths per 100,000 county residents, and the x-axis ranges from eleven weeks before to eleven weeks after the start of the semester.
Four weeks after the semester begins, the mortality difference declines to -0.7, and is -0.6 eleven weeks after the semester begins.
Source: Researchers' calculations using data from the CDC, C2i, and IPEDS