Step 1 Inclusion Criteria:  Female or male aged 15-55 years Documented negative HIV test according to site-specific HIV testing procedures at entry/screening Able and willing to provide informed consent Willing to provide biometric identification Available for follow-up for the planned study duration Understands English or the local language as approved by the IRB, including people who are illiterate Willing to provide contact information for themselves and one personal contact who would know their whereabouts during the study period Willing to provide information regarding HIV risk behaviors and to undergo testing for HIV and other STIs  Considered to be vulnerable to HIV and other STIs based on any one or more of the following test results and/or self-reported behaviors:  Documented history of newly diagnosed syphilis, gonorrhea, chlamydia, Mycoplasma genitalium, herpes simplex virus, or acute hepatitis C virus infection in the 24 weeks prior to screening Self-reported vaginal, oral, or anal intercourse in exchange for money as a regular source of income Self-reported condomless vaginal or anal intercourse with at least three different partners living with HIV or of unknown status in the 24 weeks prior to screening Self- reported injection drug use (IDU) in the 24 weeks prior to screening Self-reported insertive or receptive anal or neovaginal intercourse with one or more different male or transgender partners in the 24 weeks prior to screening  Step 2 Inclusion Criteria  New diagnosis of HIV in the last 90 days during Step 1 as determined by site-specific HIV testing procedures Able and willing to continue follow-up for the planned study duration  Step 3 Inclusion Criteria  Virally-suppressed at the completion of Step 2 Adherent to ART Able and willing to continue follow-up for the planned study duration  Step 1 Exclusion Criteria  Any significant condition (medical, psychologic/psychiatric or social) that, in the judgment of the study investigator, might interfere with the conduct of the study Active drug or alcohol use or dependence that, in the judgement of the study investigator, would interfere with adherence to study requirements Current or past participation in a preventive or therapeutic HIV vaccine study, unless known placebo recipient Positive β-HCG (human chorionic gonadotropin) pregnancy test (urine or serum) at screening for people of child-bearing potential and people who are amenorrheic for less than 12 consecutive months.  Step 2 Exclusion Criteria  Any significant condition (medical, psychologic/psychiatric or social) that, in the judgment of the study investigator, might interfere with the conduct of the study Active drug or alcohol use or dependence that, in the opinion of the investigator, would interfere with adherence to study requirements  Step 3 Exclusion Criteria  Any significant condition (medical, psychologic/psychiatric or social) that, in the judgment of the study investigator, might interfere with the conduct of the study Active drug or alcohol use or dependence that, in the opinion of the investigator, would interfere with adherence to study requirements