This is a multicenter study of COVID-19 vaccine immunogenicity and durability, and breakthrough serious acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections in people who receive a COVID-19 vaccine through their country's national vaccination programs. Participants will be enrolled upon signing the informed consent within a day of receipt of a COVID-19 vaccine (before or after). The study team will not be administering the vaccine; receipt of vaccine will be provided through each country's vaccine program. Blood specimens will be collected to measure the immune response to the vaccine. Participants may be asked to contact study staff at any time during the study for evaluation if they develop symptoms consistent with SARS-CoV-2 infection, at which time they will be counseled about the need for a medical evaluation that may include collection of an upper airway swab for diagnosis (and research) and a blood sample for research. Infections will be confirmed by molecular or antigen (Ag) testing at the time of symptoms, and swabs will be collected and stored for viral sequencing and analyses.
