A Study on the Reactogenicity, Safety, Immune Response, and Efficacy of a Targeted Immunotherapy Against HSV in Healthy Participants Aged 18-40 Years or in Participants Aged 18-60 Years With Recurrent Genital Herpes

Inclusion Criteria:

• • Participants, who, in the opinion of the investigator, can and will comply withthe requirements of the Protocol.

• Written informed consent obtained from the participant prior to performance of anystudy-specific procedure.

• Women of non-childbearing potential can be enrolled in the study.

• Women of childbearing potential can be enrolled in the study, if the participant:

• Has practiced highly effective contraception for one month prior to studyintervention administration, and,

• Has a negative pregnancy test result at the Screening visit and on the day ofeach study intervention administration, and,

• For PART I: Has agreed to continue highly effective contraception until the endof the study.

• For PART II: Has agreed to continue highly effective contraception until 3months after last study intervention administration.

• Seronegative for human immunodeficiency virus (HIV), as determined by laboratoryscreening tests. Participants documented to be seropositive to HIV will not beeligible for study participation.

• Only for PART I: Healthy participants as established by medical history and physicalexamination, at the discretion of the investigator, before entering into the study.

• Only for PART I: Man or woman aged 18 to 40 years, included, at the time of thefirst study intervention administration.

• Only for PART I: Seronegative for HSV-2 as determined by Western blot performed atthe Screening visit.

• Only for PART II: Participants with recurrent genital herpes and with no significanthealth problems as established by medical history and physical examination, at thediscretion of the investigator, before entering the study.

• Diagnosis of genital herpes for at least one year before the Screening visit.

• History of self-reported or documented recurrent lesional genital herpesfrequency of at least 3 and no more than 9 reported clinical recurrences in the 12 months preceding the screening visit, or, if still on suppressive therapywithin 3 months before the Screening visit, prior to initiation of suppressivetherapy.

• Only for PART II: Man or woman aged 18 to 60 years, included, at the time of thefirst study intervention administration.

• Only for PART II: Seropositive for HSV-2 as determined by serologicaltestingperformed at the Screening visit, or having documented laboratory-confirmedHSV 2 genital herpes (i.e., HSV-2 DNA positive by a molecular technique such aspolymerase chain reaction [PCR], or HSV-2 seropositive by a type-specific serologyassay such as Western Blot or other immunoassay).Only for PART II (sheddingsub-cohort): Participants agreeing to collect 2 swabs per day from anogenital areafor the full duration of the 5 swabbing periods planned in the study.

• Only for PART II (shedding sub-cohort) after baseline completion: Participantshaving collected at least 45 out of 56 anogenital swabs during the baseline period.

Exclusion Criteria:

Medical Conditions

• Acute or chronic clinically significant pulmonary, cardiovascular, hepatic,endocrine, or renal functional abnormality, as determined by physical examination orlaboratory screening tests.

• Any other clinical condition that, in the opinion of the investigator, might poseadditional risk to the participant due to participation in the study or that wouldinterfere with the efficacy and immunogenicity assessments planned in this study.

• History of any reaction or hypersensitivity likely to be exacerbated by anycomponent of the study intervention.

• Any confirmed or suspected immunosuppressive or immunodeficient condition, based onmedical history and physical examination.

• Hypersensitivity to latex.

• Recurrent history or uncontrolled neurological disorders or seizures.

• Haematological and/or biochemical parameters outside the normal laboratory ranges atthe Screening visit, unless the laboratory abnormalities are considered notclinically significant by the investigator.

• Body mass index =<18 kg/m^2 or >=35 kg/m^2.

• Past or current Guillain-Barré syndrome.

• History of any form of ocular HSV infection, HSV-related erythema multiforme, orHSV-related neurological complications.

Prior/Concomitant Therapy

• Use of any investigational or non-registered product other than the studyintervention during the period beginning as of the Screening visit, or planned useduring the study period.

• Planned administration/administration of a vaccine not foreseen by the Protocol inthe period starting 15 days before each dose and ending 15 days after each dose ofstudy intervention administration.

• Administration or planned administration of long-acting immune-modifying drugs atany time during the study period.

• Administration of immunoglobulins and/or any blood products or plasma derivativesduring the period starting 3 months before the first dose of study intervention orplanned administration during the study period.

• Chronic administration of immunosuppressants or other immune-modifying drugs duringthe period starting 3 months prior to the first study intervention dose. Forcorticosteroids, this will mean prednisone equivalent >= 20 mg/day, or equivalent.Inhaled, intra articular and topical steroids are allowed.

• Prior receipt of another vaccine containing HSV antigens.

• Only for PART II: Planned use of suppressive anti-HSV therapy from the Screeningvisit until the end of the study.

• Only for PART II: Planned use of tenofovir therapy, or other medication known toaffect HSV shedding or genital lesions from the Screening visit until the end of thestudy. Only for PART II: Planned use of topical antiviral medication in theanogenital region from the Screening visit until the end of the study.

• Only for PART II: Planned use of any episodic antiviral medications during theswabbing periods (including the baseline period) (only for the shedding sub-cohort).

Prior/Concurrent Clinical Study Experience

• Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non-investigational intervention.

Other Exclusions

• Pregnant or lactating women.

• Woman planning to become pregnant or planning to discontinue contraceptiveprecautions in the period starting from the Screening visit up to 3 months post-lastdose of study intervention.