State of the art about influenza vaccination for advanced cancer patients receiving immune checkpoint inhibitors: When common sense is not enough

Influenza vaccination is recommended for advanced cancer patients, since impaired immunity is presumed to be due not only to the tumor itself but also to immunosuppressive treatments, such as chemotherapy and radiotherapy. The recent advances in the systemic management of metastatic solid tumors, with the introduction of immune checkpoint inhibitors for several indications in clinical practice, has re-actualized simple clinical issues, such as the vaccinal recommendations and counseling, for which common sense is not enough to support pragmatic choices. In the present review, we summarized the evidence about influenza vaccine administration during immune checkpoint blockade, emphasizing the need of prospective data to definitely guide our advices to a growing group of cancer patients.