To Investigate Safety, Reactogenicity and Immunogenicity of VIR-1388 Compared With Placebo in Participants Without HIV

Inclusion Criteria: * In overall good health as determined by medical history, physical exam, and laboratory values * HIV uninfected * CMV seropositive * Willing to use condoms during intercourse for the duration of the study * Assessed by clinic staff as being low risk for HIV infection and committed to maintaining behavior consistent with low risk of HIV exposure through the last protocol visit * Childbearing status * Part A: Only participants of non-childbearing potential * Part B: Participants of childbearing potential must be on 2 forms of contraception and not planning on becoming pregnant for the duration of the study Exclusion Criteria: * Participant is immunocompromised * Participant has an autoimmune disorder * Participants having intimate contact with immunocompromised individuals * Participants having intimate contact with a pregnant partner or partner planning to become pregnant * Participants who are breastfeeding