Retrospective cohort study of COVID-19 vaccine booster uptake and effectiveness among US adults with cancer

Cancer patients are at increased risk of severe COVID-19 infection, but the additional benefit of COVID-19 boosters for these patients is unclear. In a retrospective cohort study among adult cancer patients of 4 US health care systems, additional monovalent COVID-19 vaccines reduced COVID-19 hospitalizations by 29%, with a number needed to vaccinate of 166 in January to August 2022, and a bivalent COVID-19 vaccine reduced COVID-19 hospitalizations by 30%, with a number needed to vaccinate of 451 in September 2022 to August 2023. The authors conclude that in both time periods, COVID-19 vaccination was associated with protection from severe COVID-19 infection among patients with cancer. However, uptake of COVID-19 vaccine boosters was low.