Retrospective cohort study of outcomes with influenza vaccination among checkpoint inhibitor- treated cancer patients

A retrospective cohort study at three centers in Sweden investigated survival outcomes and immune-related adverse events (IRAEs) with influenza vaccination among cancer patients treated with immune checkpoint inhibitors (ICIs). The study included 587 patients treated between 2016 and 2021. The most common malignancy were non-small cell lung cancer (NSCLC; 34.4%) and cutaneous melanoma (CMM; 32.5%). Real-world progression-free survival was significantly longer in influenza-vaccinated patients compared with unvaccinated patients (HR 0.59; 95% CI 0.44-0.79). This survival benefit was more pronounced among the CMM patients and was not statistically significant among the NSCLC patients. There were no statistically significant differences in the occurrence of any-grade IRAEs (48.4% versus 51.2%; p=0.455) or multiple IRAEs (15.1% versus 19.2%) between the vaccinated and unvaccinated groups. The authors conclude that these findings suggest a potential association between influenza vaccination and improved survival in CPI-treated cancer patients, without a corresponding increase in IRAEs.