This is a Phase 1, randomized, double-blind, placebo-controlled, multicenter study in adults aged 18 to 55 years in overall good health and without HIV. Participants will be enrolled concurrently into 1 of 3 dose levels of VIR-1388 or placebo. The overall study design includes 2 study parts, Part A and Part B. Part A will be a lead-in phase enrolling a limited number of HCMV seropositive persons of non-childbearing potential (PONCBP) with a frequent safety monitoring schedule. Part B will expand enrollment into a broader population of HCMV-seropositive participants, including persons of childbearing potential required to use 2 forms of contraception and maintains a similar overall safety monitoring schedule as Part A . There is an optional long-term follow-up study that would lengthen study participation for up to 3 years post-first dose.
