bHIV per 100 PY in the Incidence Phase was calculated using RITA. The RITA incorporated HIV-1 testing results and recency assay testing results to estimate the bHIV. Recency assay testing was performed for participants in the All Screened Set found to have HIV-1 infection at the Incidence Phase Screening Visit as defined below. Participants were considered to have recent HIV-1 infection if the normalized optical density (ODn) was below 1.5 threshold using the Sedia limiting antigen avidity enzyme immunoassay (LAg-EIA) and the HIV-1 RNA (viral load) was \> 75 copies/mL of blood. HIV-1 infection was defined as participants having at least one of the following central lab results at the Incidence Phase screening visit: * Positive HIV-1/2 differentiation Ab, OR * Positive HIV-1 ribonucleic acid (RNA) qualitative test, OR * HIV-1 RNA quantitative test ≥200 copies/mL.

HIV-1 incidence per 100 PY for LEN and F/TAF was calculated as the number of participants who acquired HIV-1 divided by the total of a) for participants not diagnosed with HIV-1, sum of all duration of follow-up time in years, while at risk of HIV-1 infection (where a year is 365.25 days) and b) for participants diagnosed with HIV-1, sum of all duration of follow-up time up to confirmed HIV-1 diagnoses. HIV-1 diagnosis was determined by an HIV adjudication committee who reviewed potential HIV-1 infection events in the randomized participants. The committee, in a blinded, consistent, and unbiased manner, determined whether HIV test results confirmed HIV-1 infection and determined the date of diagnosis for each case, defined as the date of the earliest study visit with evidence of HIV infection considering both prospective HIV testing and back-testing of archived samples. bHIV incidence per 100 PY in All Screened Set was estimated as described in outcome measure#1.

HIV-1 incidence per 100 PY for LEN was calculated as the number of participants who acquired HIV-1 divided by the total of a) for participants not diagnosed with HIV-1, sum of all duration of follow-up time in years, while at risk of HIV-1 infection (where a year is 365.25 days) and b) for participants diagnosed with HIV-1, sum of all duration of follow-up time up to confirmed HIV-1 diagnoses. HIV-1 diagnosis was determined by an HIV adjudication committee who reviewed potential HIV-1 infection events in the randomized participants. The committee, in a blinded, consistent, and unbiased manner, determined whether HIV test results confirmed HIV-1 infection and determined the date of diagnosis for each case, defined as the date of the earliest study visit with evidence of HIV infection considering both prospective HIV testing and back-testing of archived samples. bHIV incidence per 100 PY in All Screened Set was estimated as described in outcome measure#1.

This outcome measure will compare LEN and F/TDF persistence through 52 weeks, where persistence is defined by On-time LEN Injection at Day 1/Baseline and Week 26 and On-time Follow-up Visit at Week 52 for LEN arm and by Adherence Levels Based on tenofovir diphosphate (TFV-DP) concentrations in red blood cells consistent with ≥ 4 doses/week (≥ 700 fmol/punch) in dried blood spot (DBS) at Weeks 13, 26, 39, and 52 for F/TDF arm.

Ctrough is defined as the concentration at the end of the dosing interval.

Ctrough is defined as the concentration at the end of the dosing interval.

To assess the acceptability of the study drug, participants will complete the questionnaire including a question on general acceptability of the assigned study drug on an ordinal 5-category scale with a response of: Completely unacceptable, Unacceptable, No opinion, Acceptable, or Completely acceptable.

To assess the satisfaction with use of the study drug, participants will complete the questionnaire including a question on satisfaction with use of the assigned study drug on an ordinal 5-category scale with a response of: Very satisfied, Satisfied, Neutral, Dissatisfied, or Very dissatisfied.

To assess the willingness to use the study drug, participants will complete the questionnaire including a question on willingness to use the assigned study drug on an ordinal 5-category scale with a response of: Definitely Yes, Probably yes, Not sure/undecided, Probably No, or Definitely No.