Inclusion Criteria:  Adults from Melanesian, Polynesian, European or other community origin Adults vaccinated with 2 doses of Pfizer COMIRNATY vaccine, administered between 3 and 12 weeks apart Adults planning to be present in the territory and to be available on both sampling dates (1 and 6 months)  Exclusion Criteria:  Persons who received the second dose of vaccine more than 12 weeks after the first dose Persons vaccinated against COVID-19 with a vaccine other than Pfizer COMIRNATY Women who report being pregnant or breastfeeding (where the immune response may be altered) Immunocompromised persons (immunosuppressive treatment, immunomodulator, HIV positive, splenectomy, long term corticosteroid therapy, autoimmune diseases such as rheumatoid arthritis, lupus, spondyloarthritis, etc.) People who are not intellectually capable of answering the questionnaire Persons under guardianship, curatorship or any other legal incapacity Persons with documented Covid-19 infection (known positive SARS-CoV-2 serology prior to inclusion, positive PCR or antigen test)