inclusion criteria: * adult person, man or woman, staff of the clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), having received the second dose of vaccine (or the single dose if the single-dose vaccination schedule) against covid- 19 3 months +/- 15 days before the inclusion visit, as part of the national vaccination campaign, regardless of the type of vaccine administered. * for the subgroup included before vaccination (study of the pre-vaccination cellular response): adult person, man or woman, staff of clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), receiving the 1st injection on the same day or in the 7 days before the inclusion visit, regardless of the type of vaccine administered * commitment to respect the schedule of visits provided for in the research protocol * able to give informed consent to participate in research * affiliation to a social security scheme

inclusion criteria: * adult person, man or woman, staff of the clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), having received the second dose of vaccine (or the single dose if the single-dose vaccination schedule) against covid- 19 3 months +/- 15 days before the inclusion visit, as part of the national vaccination campaign, regardless of the type of vaccine administered. * for the subgroup included before vaccination (study of the pre-vaccination cellular response): adult person, man or woman, staff of clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), receiving the 1st injection on the same day or in the 7 days before the inclusion visit, regardless of the type of vaccine administered * commitment to respect the schedule of visits provided for in the research protocol * able to give informed consent to participate in research * affiliation to a social security scheme

inclusion criteria: - adult person, man or woman, staff of the clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), having received the second dose of vaccine (or the single dose if the single-dose vaccination schedule) against covid- 19 3 months +/- 15 days before the inclusion visit, as part of the national vaccination campaign, regardless of the type of vaccine administered. - for the subgroup included before vaccination (study of the pre-vaccination cellular response): adult person, man or woman, staff of clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), receiving the 1st injection on the same day or in the 7 days before the inclusion visit, regardless of the type of vaccine administered - commitment to respect the schedule of visits provided for in the research protocol - able to give informed consent to participate in research - affiliation to a social security scheme

inclusion criteria: - adult person, man or woman, staff of the clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), having received the second dose of vaccine (or the single dose if the single-dose vaccination schedule) against covid- 19 3 months +/- 15 days before the inclusion visit, as part of the national vaccination campaign, regardless of the type of vaccine administered. - for the subgroup included before vaccination (study of the pre-vaccination cellular response): adult person, man or woman, staff of clermont-ferrand university hospital (medical or paramedical, medico-technical or administrative caregiver), receiving the 1st injection on the same day or in the 7 days before the inclusion visit, regardless of the type of vaccine administered - commitment to respect the schedule of visits provided for in the research protocol - able to give informed consent to participate in research - affiliation to a social security scheme