It is a multicenter study on the immunogenicity and durability of vaccines against COVID-19 and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections in people receiving a COVID-19 vaccine through the national program of vaccination.

Previous SARS-CoV-2 infection/immunity will be measured. Immune response to vaccine and SARS-CoV-2 infection is measured at visits 2 and 10 months after completion of an initial or booster regimen. The durability of the immune response is captured through 2 optional extended follow-up visits. Symptomatic SARS-CoV-2 infections during the study are evaluated by virus detection and viral genomic sequencing. The analyzes will estimate the vaccine immunogenicity for the different vaccines in the study countries and in subgroups, including, but not limited to, HIV, pregnancy, tuberculosis and diabetes.