A Study on the Reactogenicity, Safety and Immune Response of a Vaccine Against Herpes Simplex Virus (HSV)-2 in Healthy Participants Aged 18-40 Years

The purpose of this first-time-in-human (FTiH) study is to assess the reactogenicity, safety and immunogenicity of four different dose levels of an experimental herpes simplex virus type 2 (HSV-2) vaccine, when administered intramuscularly (IM) on a 0, 2-month schedule to healthy participants aged 18-40 years.


Eligibility Criteria:
Inclusion Criteria:

* Participants, who, in the opinion of the investigator, can and will comply with the requirements of the Protocol.
* Written informed consent obtained from the participant prior to performance of any study-specific procedure.
* Healthy participants as established by medical history and clinical examination before entering into the study.
* Man or woman aged 18-40 years, included, at the time of the first vaccination.
* 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 adequate contraception for one month prior to vaccination, and;
  * Has a negative pregnancy test result on the day of vaccination, and;
  * Has agreed to continue adequate contraception until the end of the study.
* Seronegative for HIV, as determined by laboratory screening tests. Participants documented to be positive to HIV will not be eligible for study participation.
* Seronegative for HSV-2 as determined by Western blot.

Exclusion Criteria:

Medical Conditions

* Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study.
* History of any reaction or hypersensitivity likely to be exacerbated by any component of the study vaccines.
* Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination.
* Hypersensitivity to latex.
* Acute or chronic clinically significant pulmonary, cardiovascular, hepatic, endocrine, or renal functional abnormality, as determined by physical examination or laboratory screening tests.
* Recurrent history or uncontrolled neurological disorders or seizures.
* Grade 2 or higher haematological and/or biochemical laboratory abnormality at screening.
* Body mass index ≤ 18 kg/m\^2 or ≥ 35 kg/m\^2.
* History of any form of ocular HSV infection, HSV-related erythema multiforme, or HSV-related neurological complications.
* Participants with symptoms suggestive of Coronavirus disease 2019 (COVID-19) infection within 14 days before the first study vaccination. Participants should be free of symptoms for at least 14 days.
* Participants with known COVID-19-positive contacts in the past 14 days before the first study vaccination.

Prior/Concomitant Therapy

* Use of any investigational or non-registered product other than the study vaccines during the period beginning 30 days before the first dose of study vaccine (Day -29 to Day 1), or planned use during the study period.
* Planned administration/administration of a vaccine not foreseen by the Protocol in the period starting 15 days before each dose and ending 15 days after each dose of study vaccine administration.
* Administration of long-acting immune-modifying drugs at any time during the study period.
* Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting three months before the first dose of study vaccine or planned administration during the study period.
* Chronic administration of immunosuppressants or other immune-modifying drugs during the period starting three months prior to the first study vaccine dose. For corticosteroids, this will mean prednisone equivalent ≥ 20 mg/day, or equivalent. Inhaled and topical steroids are allowed.
* Prior receipt of another vaccine containing HSV-2 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 vaccine/product.

Other Exclusions

* Pregnant or lactating woman.
* Woman planning to become pregnant or planning to discontinue contraceptive precautions.