A Study on the Reactogenicity, Safety and Immune Response of a Targeted Immunotherapy Against HSV in Healthy Japanese Participants Aged 18-40 Years (TH HSV REC-004)

Inclusion Criteria: • Participants who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the diary cards, return for follow-up visits). Written informed consent obtained from the participant prior to performance of any study-specific procedure. Healthy participants as established by medical history and physical examination, at the discretion of the investigator, before entering into the study. Man or woman aged 18 to 40 years, included, at the time of screening. Japanese ethnic origin (defined as having been born in Japan with 4 ethnic Japanese grandparents and able to speak Japanese). Women of non-childbearing potential may be enrolled in the study. Women of childbearing potential may be enrolled in the study, if the participant: Has practiced highly effective contraception for 1 month prior to study intervention administration, and Has a negative pregnancy test result at the Screening visit and on the day of each study intervention administration, and Has agreed to continue highly effective contraception until Day 118, approximately 3 months post-Dose 2. Blood sample for simultaneous FSH and estradiol levels may be collected and tested locally at the discretion of the investigator to confirm non-reproductive potential according to local laboratory reference range. • Seronegative for HSV-2 as determined by Western blot performed at the Screening visit. Exclusion Criteria: Medical conditions: Acute or chronic clinically significant pulmonary, cardiovascular, hepatic, endocrine, or renal functional abnormality, as determined by physical examination or laboratory screening tests. Clinically significant abnormalities may include but are not limited to: evidence of cardiac damage, heart failure categorized as class II or greater according to the New York Heart Association functional classification, heart valve disease, pulmonary uncontrolled persistent asthma despite treatment, uncontrolled diabetes, or disease or disorder that may put the participant at risk or influence study results. Participants with a controlled underlying chronic co-morbidity may be enrolled, provided there have been no changes to their medication within 3 months prior to the Screening visit. Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study or that would interfere with the immunogenicity assessments planned in this study. History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention. Any confirmed or suspected immunosuppressive or immunodeficient condition or documented or suspected HIV infection, based on medical history and physical examination (no laboratory testing required). Hypersensitivity to latex. Recurrent history of or uncontrolled neurological disorders or seizures. At the screening visit: hematological parameters (hemoglobin level, white blood cell, platelet) and/or biochemical parameters (ALT, AST, creatinine, blood urea nitrogen) outside the normal laboratory ranges, unless the laboratory abnormalities are considered not clinically significant by the investigator. Body mass index =18 kg/m2 or =35 kg/m2. History of any form of ocular HSV infection, HSV-related erythema multiforme, or HSV-related neurological complications (including meningitis, encephalitis, radiculopathy, myelitis). Prior/Concomitant therapy: Use of any investigational or non-registered product (drug, vaccine or invasive medical device) other than the study intervention during the period beginning as of the Screening visit, or their planned use during the study period. Planned administration or administration of a vaccine* in the period starting 15 days* before each dose and ending 15 days* after each dose of study intervention administration**. * In case of adjuvanted and live-attenuated vaccines, this time window is to be increased to 30 days before and after each dose. In case emergency mass vaccination for an unforeseen public health threat (e.g., a pandemic) is recommended and/or organized by public health authorities outside the routine immunization program, the time period described above can be reduced if, necessary for that vaccine, provided it is used according to the local governmental recommendations and that the Sponsor is notified accordingly. Administration or planned administration of long-acting immune-modifying drugs at any time during the study period (e.g., infliximab). Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting 3 months before the first dose of study intervention or planned administration during the study period. Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs during the period starting 3 months prior to the first study intervention dose. For corticosteroids, this will mean prednisone equivalent =20 mg/day for adult participants. Inhaled, intra articular and topical steroids are allowed. Prior receipt of a vaccine containing HSV antigens. 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 (drug or invasive medical device). Other exclusions: • Pregnant or lactating woman. Woman planning to become pregnant or planning to discontinue contraceptive precautions before Day 118 (approximately 3 months post-Dose 2).