Retrospective Study of COVID-19 Vaccines in Patients Undergoing Immunotherapy for Cancer.

The investigators wish to set up a pharmaco-epidemiological cohort within the Hospital Territorial Groups of the Cévennes-Gard Camargue, East-Hérault and Haute-Garonne and West Tarn on a specific population, patients undergoing immunotherapy for cancer, as currently there is no data available under "real life" conditions following anti-COVID vaccination19. The hypothesis is that patients undergoing immunotherapy will not develop more vaccine-related adverse events than those observed in the efficacy and safety validation studies of the BNT162b2 mRNA Covid-19, mRNA-1273 SARS CoV-2, Oxford/AstraZeneca and Ad26COV2.S, JMJ Vaccine or J \& J COVID-19 Vaccine.

Inclusion Criteria: * Patient having been vaccinated or eligible for inoculation with one of the available anti-COVID19 vaccines (except live attenuated virus) while they were or are undergoing immunotherapy with anti-PD1, anti-PDL1 or anti-CTLA4 immunotherapy whatever the tumor (solid, liquid) managed within the medical oncology services of the Occitanie region. * Patients affiliated to or beneficiaries of a health insurance scheme. * Patients who have received written and oral information about the study and who have no objection to participation. * Adult patients (≥ 18 years). Exclusion Criteria: * Patients who have been vaccinated with a live attenuated vaccine. * Patients with a contraindication to inclusion (including hypersensitivity to the active substance or to one of the excipients, COVID+ PCR test in the last 3 months). * Minor patients, pregnant women, parturients, nursing mothers, persons in nursing mothers, persons in emergency situations, persons unable to persons unable to express their consent and persons under persons under court protection, subguardianship or subguardianship may not be included in this research. * Patients in an exclusion period determined by another study. * Patients for whom it is impossible to give clear information. * Patients who have expressed an objection to participating in the study.