Influenza Vaccination in Patients Receiving Immune Checkpoint Inhibitor

Inclusion Criteria: * Solid cancer patients receiving immune checkpoint inhibitor or cytotoxic chemotherapeutic agent in Seoul National University Hospital or Seoul National University Bundang Hospital. * Patients who was not vaccinated for influenza in 2018-2019 season * ECOG performance status 0 or 1 * Patients who fulfilling following laboratory criteria Total bilirubin ≤ 1.5 x upper normal limit Aspartate transaminase, alanine transaminase ≤ 2.5 x upper normal limit Alkaline phosphatase ≤ 2.5 x upper normal limit Creatinine ≤ upper normal limit * Patients who can understand and agreed with the informed consents. Exclusion Criteria: * Patients having contraindication for influenza vaccination (e.g. egg allergy) * Patients who receive any immunosuppressant (excluding steroid for anti-emetic effect) * Patients with HIV infection * Patients with autoimmune disease who are anticipated to have a problem with immunogenicity for vaccine * Patients who have transplanted organ and receive immunosuppressants * Patients who are suspected to have active infection (e.g. pneumonia) * Patients who receive targeted chemotherapeutic agent alone for cancer treatment * Patients who could not receive cancer chemotherapy due to hematologic abnormality at the date of the participation