Does Flu Vaccination Affect Risk of Immune-Related Adverse Events from Specific Immune Checkpoint Inhibitors?

A study highlighted at the 2021 ASCO Annual Meeting explored whether patients who received an influenza vaccine were at increased risk for immune-related adverse events from single-agent immune checkpoint inhibitors.

Receiving an influenza vaccine does not increase the risk of immune-related adverse events (irAEs) for patients being treated with single-agent immune checkpoint inhibitors (ICIs) for cancer, according to the results of a study.

The study results were highlighted at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, which is being held virtually from June 4-8, 2021.

Previous analyses have evaluated the effect of influenza vaccinations on the incidence and severity of irAEs in this patient population with varying results. However, the most common medication investigated was ipilimumab, and there is limited data for those receiving program death-1 (PD-1) and the program death ligand-1 (PD-L1) inhibitors.

For the study, investigators conducted a retrospective chart review of patients 18 to 89 years old who received single-agent pembrolizumab, nivolumab, atezolizumab, or durvalumab at an academic medical center from August 2015 to August 2019.


Of the 217 charts screened, 133 were included in the study. Fifty-three patients were included in the influenza vaccination group and 80 patients were included in the group that did not receive influenza vaccinations. The most common cancer diagnoses in the study were lung cancer and melanoma. Ninety-one percent of patients in the vaccination group versus 81% in the group who did not get an influenza vaccination received either nivolumab or pembrolizumab.

The investigators reported that there was no statistical difference in irAEs in those who received an influenza vaccine versus those who did not (30% versus 45%, P=0.15). Moreover, the only significant secondary outcome identified was the rate of irAEs in patients receiving a PD-1 inhibitor versus a PD-L1 inhibitor regardless of vaccination status (42.2% versus 11.1%, P=0.03).

Overall, the investigators noted that the study results demonstrate no increased risk of irAEs in those receiving ICIs, specifically PD-1 and PD-L1 inhibitors, who received an influenza vaccine. These outcomes may been influenced by adherence issues with yearly influenza vaccinations, inaccurate vaccination records, and receiving vaccines out of state.

Larger population studies are needed to validate these findings and identify the risk and benefit of patients receiving their annual influenza vaccine while on these treatments, the investigators concluded.


  1. Naga MV, Corcoran C, Comeau J, et al. Effect of influenza vaccination on immune-related adverse events in patients receiving single-agent immune checkpoint inhibitors for the treatment of cancer. 2021 American Society of Clinical Oncology Annual Meeting; June 4-8, 2021; virtual. Accessed June 2, 2021.