Safety and Pharmacokinetics of Oral Islatravir (MK-8591) Once Monthly in Participants at Low Risk of Human Immunodeficiency Virus 1 (HIV-1) Infection (MK-8591-016)

- Is in general good health with acceptable laboratory values at screening

- Is confirmed HIV-uninfected based on negative HIV-1/HIV-2 test result before randomization

- Has low risk of HIV infection, within 12 months prior to screening visit or the rescreening visit (if applicable)

- Use contraceptives consistent with local regulations

- Female is not pregnant or breastfeeding, and is not a woman of childbearing potential (WOCBP)

- A WOCBP is using an acceptable contraceptive method, or is abstinent from heterosexual intercourse as their preferred and usual lifestyle; or has a negative pregnancy test.

- Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator

- Has an active diagnosis of hepatitis due to any cause

- Has a history of malignancy ≤5 years prior to signing informed consent except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer.

- Is taking or is anticipated to require systemic immunosuppressive therapy, immune modulators, or any prohibited therapies from 30 days prior to Day 1 through the duration of the study.

- Is currently participating in or has participated in an interventional clinical study with an investigational compound or device within 30 days prior to Day1 through the duration of the study.

- Has previously been randomized in a study and received islatravir (MK-8591).

- Female is expecting to conceive or donate eggs at any time during the study

- Has QTc interval (using Fridericia correction) >450 msec (for males) or >460 msec (for females) or deemed clinically abnormal by the investigator.