Although patients with cancer have poor COVID-19–related outcomes,
1-4 the effectiveness of SARS-CoV-2 vaccination in this population is unclear because they were excluded from vaccination trials.
5,6 Recent studies suggest that patients with cancer mount less robust antibody responses to vaccination than immunocompetent controls.
7-10 The objective of this retrospective cohort study in the national Veterans Affairs (VA) health care system was to estimate the SARS-CoV-2 vaccination effectiveness in patients with cancer in a real-world setting during the 140-day period following initial vaccine availability.