A Study of mRNA-1608, a Herpes Simplex Virus -2 (HSV-2) Therapeutic Candidate Vaccine, in Healthy Adults 18 to 55 Years of Age With Recurrent HSV-2 Genital Herpes

Inclusion Criteria: * Participant has a diagnosis of genital HSV-2 infection for at least 1 year before the Screening Visit. * Seropositive for HSV-2 as determined by Western Blot. * Participant has a history of recurrent genital herpes defined as at least 3 and no more than 9 reported genital herpes recurrences in the 12 months preceding the Screening Visit, or if currently on suppressive therapy, prior to initiation of suppressive therapy. * Willing to refrain from taking suppressive antiviral therapy from the Screening Visit until the end of the study. * Willing to refrain from the use of episodic antiviral therapy during the three 28-day anogenital swabbing periods. Episodic therapy may be used outside the three 28-day swabbing periods. * For female participants of childbearing potential: negative pregnancy test, adequate contraception, and not currently breastfeeding. Exclusion Criteria: * Prior immunization with a vaccine containing HSV antigens. * History of any form of ocular HSV infection, HSV-related erythema multiforme, or HSV-related neurological complications. * History of genital HSV-1 infection. * History of hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) types 1 or 2 (HIV-1, HIV-2). * Reported history of anaphylaxis or severe hypersensitivity reaction after receipt of any mRNA vaccine(s) or any components of the mRNA vaccines. * Previously received BEXSERO or other vaccine to prevent serogroup B meningococcal disease (also known as meningiti…