The study is constructed to help inform which vaccine regimen, likely in combination with enhanced HIV care, could serve as a public health model for an effective and cost-efficient approach to preventing SARS-CoV-2 disease, prolonged viral shedding, and the emergence of VOCs within this population. Moreover, we will evaluate whether immune responses postvaccination can be correlated to these clinically important outcomes.~The study will enroll 15,600 adults from many clinics in Eastern and Southern Africa. All participants in the study will get the study vaccine. There are 4 primary groups in this study. The groups differ in the number of doses of the study vaccine administered. The groups are organized by whether or not people are living with HIV and whether or not people have evidence of prior SARS-CoV-2 infection in their blood.~Group 1 includes people living with HIV and Group 3 includes people who are not living with HIV. All people in groups 1 and 3 will have no evidence of prior SARS-CoV-2 infection in their blood. Participants in Group 1 or Group 3 will get three doses of the study vaccine.~Group 2 includes people living with HIV and Group 4 includes people who are not living with HIV. All people in groups 2 and 4 will have evidence of prior SARS-CoV-2 infection in their blood. Participants in Group 2 or Group 4 will get two doses of the study vaccine.~There are 8 scheduled clinic visits over 18 months. Study visits may include physical examinations, medical history, vaccine injections, HIV testing, blood collection, nasal swabs, and questionnaires.
The study will evaluate the clinical efficacy of different dosing regimens of the Moderna COVID-19 mRNA vaccine (100 mcg) in preventing COVID-19 disease in people who are living with HIV or have comorbidities associated with elevated risk of severe COVID-19, with the different vaccine regimens assessed determined by whether the participant had evidence of prior SARS-CoV-2 infection at enrollment.