This funding supports a multicenter study of COVID-19 vaccine immunogenicity and durability, and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections in people who receive a COVID-19 vaccine through their country’s national vaccination programs. The study will be conducted in international sites including those that participate in the Division of Clinical Research Special Projects. This study is unique in that it examines the immunogenicity of multiple different vaccination regimens (both initial and booster) across several countries.