inclusion criteria: 1. age ≥ 18 years 2. adult in a healthy condition or with a stable health status if pre-existing medical history. stable health status is defined as an existing disease that has not required a significant change in treatment of hospitalization for worsening in the 3 months before enrollment, and for which neither a significant change in treatment or hospitalization for worsening is expected in the near future 3. for women of childbearing age: a negative highly sensitive pregnancy urinary test during the inclusion visit and use of an effective contraceptive method prior to vaccination and until at least 12 weeks after the vaccination 4. who has received 2 doses of mrna vaccine (pfizer-biontech) with an interval of 3 to 6 weeks 5. second dose of mrna vaccine (pfizer-biontech) administered 6 months +/- 1 month before the booster dose 6. understands and agrees to comply with the study procedures 7. written informed consent signed by both the participant and the investigator 8. subject affiliated to the french social security system.

inclusion criteria: 1. age ≥ 18 years 2. adult in a healthy condition or with a stable health status if pre-existing medical history. stable health status is defined as an existing disease that has not required a significant change in treatment of hospitalization for worsening in the 3 months before enrollment, and for which neither a significant change in treatment or hospitalization for worsening is expected in the near future 3. for women of childbearing age: a negative highly sensitive pregnancy urinary test during the inclusion visit and use of an effective contraceptive method prior to vaccination and until at least 12 weeks after the vaccination 4. who has received 2 doses of mrna vaccine (pfizer-biontech) with an interval of 3 to 6 weeks 5. second dose of mrna vaccine (pfizer-biontech) administered 6 months +/- 1 month before the booster dose 6. understands and agrees to comply with the study procedures 7. written informed consent signed by both the participant and the investigator 8. subject affiliated to the french social security system.

inclusion criteria: age ≥ 18 years adult in a healthy condition or with a stable health status if pre-existing medical history. stable health status is defined as an existing disease that has not required a significant change in treatment of hospitalization for worsening in the 3 months before enrollment, and for which neither a significant change in treatment or hospitalization for worsening is expected in the near future for women of childbearing age: a negative highly sensitive pregnancy urinary test during the inclusion visit and use of an effective contraceptive method prior to vaccination and until at least 12 weeks after the vaccination who has received 2 doses of mrna vaccine (pfizer-biontech) with an interval of 3 to 6 weeks second dose of mrna vaccine (pfizer-biontech) administered 6 months +/- 1 month before the booster dose understands and agrees to comply with the study procedures written informed consent signed by both the participant and the investigator subject affiliated to the french social security system.

inclusion criteria: age ≥ 18 years adult in a healthy condition or with a stable health status if pre-existing medical history. stable health status is defined as an existing disease that has not required a significant change in treatment of hospitalization for worsening in the 3 months before enrollment, and for which neither a significant change in treatment or hospitalization for worsening is expected in the near future for women of childbearing age: a negative highly sensitive pregnancy urinary test during the inclusion visit and use of an effective contraceptive method prior to vaccination and until at least 12 weeks after the vaccination who has received 2 doses of mrna vaccine (pfizer-biontech) with an interval of 3 to 6 weeks second dose of mrna vaccine (pfizer-biontech) administered 6 months +/- 1 month before the booster dose understands and agrees to comply with the study procedures written informed consent signed by both the participant and the investigator subject affiliated to the french social security system.

inclusion criteria: age ≥ 18 years adult in a healthy condition or with a stable health status if pre-existing medical history. stable health status is defined as an existing disease that has not required a significant change in treatment of hospitalization for worsening in the 3 months before enrollment, and for which neither a significant change in treatment or hospitalization for worsening is expected in the near future for women of childbearing age: a negative highly sensitive pregnancy urinary test during the inclusion visit and use of an effective contraceptive method prior to vaccination and until at least 12 weeks after the vaccination who has received 2 doses of mrna vaccine (pfizer-biontech) with an interval of 3 to 6 weeks second dose of mrna vaccine (pfizer-biontech) administered at least 6 months before the booster dose understands and agrees to comply with the study procedures written informed consent signed by both the participant and the investigator subject affiliated to the french social security system.

inclusion criteria: age ≥ 18 years adult in a healthy condition or with a stable health status if pre-existing medical history. stable health status is defined as an existing disease that has not required a significant change in treatment of hospitalization for worsening in the 3 months before enrollment, and for which neither a significant change in treatment or hospitalization for worsening is expected in the near future for women of childbearing age: a negative highly sensitive pregnancy urinary test during the inclusion visit and use of an effective contraceptive method prior to vaccination and until at least 12 weeks after the vaccination who has received 2 doses of mrna vaccine (pfizer-biontech) with an interval of 3 to 6 weeks second dose of mrna vaccine (pfizer-biontech) administered at least 6 months before the booster dose understands and agrees to comply with the study procedures written informed consent signed by both the participant and the investigator subject affiliated to the french social security system.