Doravirine/Islatravir (DOR/ISL) in Pediatric Participants With Human Immunodeficiency Virus Type 1 (HIV-1) Who Are <18 Years of Age and Weigh ≥35 kg (MK-8591A-028)

Inclusion Criteria: * Is HIV-1 positive, is \<18 years of age, and weighs ≥35 kg at screening. * VS Participants: Is HIV-1 positive at Screening with plasma HIV-1 RNA \<50 copies/mL and has been receiving continuous, stable oral 2-drug or 3-drug combination ART ± PK booster with documented viral suppression for ≥3 months prior to providing documented informed consent/assent and has no history of prior virologic treatment failure on any past or current regimen. * TN Participants: Is HIV-1 positive at Screening with plasma HIV-1 RNA ≥500 copies/mL and is naive to ART defined as having received \<=10 days of prior therapy with any antiretrovirals following HIV-1 diagnosis other than pre-exposure prophylaxis (PrEP) or potentially exposed person (PEP). * If female, is not pregnant or breastfeeding, and is either 1) not a woman of childbearing potential (WOCBP) or 2) is a WOCBP and is using acceptable contraception or is abstinent. Exclusion Criteria: * Has HIV-2 infection. * Has hypersensitivity or other contraindication to any of the components of the study drugs as determined by the investigator. * Has an active diagnosis of hepatitis due to any cause, including active hepatitis B virus (HBV) infection (defined as hepatitis B surface antigen \[HBsAg\]-positive or HBV deoxyribonucleic acid \[DNA\] positive). * Has a history of malignancy ≤5 years prior to providing documented informed consent except for adequately treated basal cell or squamous cell skin cancer, in situ cervic…