What is already known about this topic?
Data are limited regarding the risks for SARS-CoV-2 infection and hospitalization after COVID-19 vaccination and previous infection.
What is added by this report?
During May–November 2021, case and hospitalization rates were highest among persons who were unvaccinated without a previous diagnosis.
Before Delta became the predominant variant in June, case rates were higher among persons who survived a previous infection than persons who were vaccinated alone.
By early October, persons who survived a previous infection had lower case rates than persons who were vaccinated alone.