*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.