COVID-19-Study of Immune Responses Following Vaccination Against SARS-CoV-2

\*Inclusion Criteria: * Male or female patients * Age ≥ 18 years * Not having developed a symptomatic form of COVID-19 within the last 3 months before inclusion * Eligible to the vaccination against SARS-CoV-2 * Affiliation to French social security or receiving such a regime, * Signed informed consent * Ability to comply with the study protocol, in the Investigator's judgment Cancer patients * Patients under active anticancer treatment: in adjuvant or neoadjuvant setting or in first line of treatment in metastatic setting. Except for prostate cancer (until metastatic castration-resistant prostate cancer); and breast cancer hormonal receptor positive/HER2 negative (until apparition of hormonal resistance). * Patients in follow-up (active treatment \< 3 months). Elderly: Age ≥ 70 years old Healthy person: Age ≥ 18 years old and \< 70 years old \*Exclusion Criteria: * Patient under guardianship, guardianship or under the protection of justice * Receipt of a live, attenuated vaccine within 4 weeks prior to the initiation of treatment or anticipation that such a live, attenuated vaccine will be required during the study.