Introduction: Patients with non-small cell lung cancer (NSCLC) are at high risk of severe influenza and invasive pneumococcal infections. Literature data on the effect of influenza vaccination on the incidence of immune-related Adverse Events (irAEs) under immunotherapy are contradictory (Wijn. D.H. et al, Eur J Cancer. Nov 2018;104:182-7), (Läubli. H., et al, J Immunother Cancer 2018;6(1):40) and there are no data on the effect of pneumococcal vaccination. Aims and objectives: Our objective is therefore to study the effect of influenza and pneumococcal vaccination on the incidence of irAEs in patients receiving immunotherapy for advanced stage NSCLC. Methods: Patients included began immunotherapy between August, 2018 and April, 2019 at the Bordeaux University Hospital. Vaccination status for influenza and pneumococcus was collected retrospectively, as was the occurrence of irAEs within 6 months, grade of severity, onset time and type of irAEs. Of the 80 patients included in the study, 31 were not vaccinated, 36 were vaccinated for influenza and pneumococcus and 13 had pneumococcal vaccine or influenza vaccine only. The overall incidence of irAEs was 25.0%. For double vaccinated patients it was 19.4% and 29.0% for unvaccinated patients (p = 0.401). The majority of irAEs were mild (88.0%) and occurred early. The incidence of irAEs in patients receiving immunotherapy for advanced NSCLC has not increased when patients were vaccinated for influenza and pneumococcus< Réduire