Influenza vaccination during treatment with immune checkpoint inhibitors (ICI) is associated with significantly improved progression-free and overall survival, particularly among patients with cutaneous malignant melanoma, according to a study published in February 2026 in JCO Oncology Practice.
Investigators from Sweden conducted the research, which builds on a growing body of evidence suggesting a beneficial link between flu shots and outcomes for cancer patients undergoing immunotherapy. A secondary analysis of the INVIDIa-2 study, published in The Lancet, also aimed to assess patient outcomes based on vaccine administration.
Immune checkpoint inhibitors work by helping the immune system recognize and attack cancer cells. However, as these drugs modulate the immune system, clinicians have expressed concern that administering vaccines, like the influenza vaccine, could potentially increase the risk of immune-related adverse events. A systematic review and meta-analysis published in 2022 in Vaccines sought to address this concern, examining the safety and efficacy of influenza vaccination in cancer patients receiving ICI treatment.
The recent findings offer reassurance on that front. According to Managed Healthcare Executive, the Swedish study found no increase in immune-related adverse events among vaccinated patients. Curetoday.com reported that the findings are “reassuring,” indicating the flu shot is safe during immunotherapy.
The INVIDIa-2 study, a prospective multicentre observational trial, investigated the clinical effectiveness of influenza vaccination in patients with advanced cancer receiving ICI. The analysis focused on how vaccine administration impacted immunotherapy outcomes.
Researchers at The University of Texas MD Anderson Cancer Center, McGill University and The University of Texas Health Science Center contributed to the 2022 systematic review, which analyzed multiple studies reporting the effects of influenza vaccination in cancer patients during ICI treatment.
