A recent study in the journal PNAS has demonstrated that influence vaccination in cancer patients makes them more susceptible to immune checkpoint inhibitors like Keytruda. In addition, vaccination was able to change the tumor microenvironment from an immune-suppressive state to an inflammatory state.

What the authors have described here is a dual-advantage approach. While they demonstrate that influenza vaccination is able to bolster anti-tumor immunity and sensitize the cancer to immunotherapy, they also argue that vaccinating cancer patients may prevent them from future/ recurrent flu infections. This is a compelling argument since flu infections are a widespread and serious problem in cancer patients whose immune systems are weakened, making them a susceptible population.

With regards to the real-world implications of these findings, 2 things stand out :

The flu vaccine is already FDA-approved, thus making it easily accessible to patients for wider use

The authors only observed significantly effective anti-tumor immune responses when the vaccine was given intratumorally. Depending on the location of the tumor, this may not be a feasible option for all patients