The current clinical study will evaluate the GVGH Quadrivalent Pan-Salmonella vaccine for the first time in healthy adults in Africa. The purpose of the current Phase 1 study is to evaluate the safety, reactogenicity, and the immune response induced by the Pan-Salmonella vaccine.

Inclusion Criteria:

1. 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).

2. Written informed consent obtained from the participant prior to performance of any study specific procedure.

3. Healthy participants as established by medical history, clinical examination, and laboratory assessment*.

   *Hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies, and human immunodeficiency virus (HIV) antibodies will also be tested at Screening.

4. A male or female between and including 18 to 45 years of age at the time of the first study intervention administration, and no older than 45 years of age at second dose administration.

5. Female participants of nonchildbearing potential may be enrolled in the study. Nonchildbearing potential is defined as pre-menarche, current bilateral tubal ligation or occlusion, hysterectomy, bilateral ovariectomy, or menopause.

6. Participants of childbearing potential may be enrolled in the study if the participant:

   • Has practiced adequate contraception (as indicated in Section 10.5) for at least 30 days prior to study intervention administration, and
   • Has a negative pregnancy test within 24 hours prior to the study intervention administration, and
   • Has agreed to continue adequate contraception during the entire treatment period and for 8 weeks after completion of the study intervention administration series.

7. Negative HLA-B27 testing.

8. Body mass index of 18>= to <=30 kg/m2 at Screening.

9. Living in the study area and plan to remain in the study area for the study duration.

Exclusion Criteria:

Medical Conditions:

1. Known exposure to S. Typhi, S. Paratyphi A, and non-typhoidal Salmonella confirmed by blood culture during the period starting 3 years prior to first study intervention administration as confirmed using medical history.

2. History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention.

3. Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).

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

5. Recurrent history or uncontrolled neurological disorders or seizures.

6. Any clinically significant hematological and/or biochemical laboratory abnormality.

7. Clinical conditions representing a contraindication to intramuscular (IM) injections and/or blood draws.

8. Any behavioral or cognitive impairment or psychiatric disease that in the opinion of the Investigator, may interfere with the participant's ability to participate in the study.

9. Acute or chronic illness which may be severe enough to preclude participation.

10. Any other clinical condition that, in the opinion of the Investigator, might pose additional risk to the participant due to participation in the study.

    Prior/Concomitant Therapy:

11. History of receiving any typhoid vaccine (Ty21a, Vi capsular polysaccharide, or TCV) in the participant's life.

12. History of receiving any investigational iNTS, S. Paratyphi A, or GMMA vaccines in the participant's life.

13. Use of any investigational or non-registered product (drug, vaccine, or medical device) other than the study interventions during the period beginning 30 days (Days -30 to 1) before the first dose of study interventions, or their planned use during the study period.

    Use of herbs and traditional treatments is not considered an exclusion criterion.

14. A vaccine not foreseen by the study protocol administered during the period starting at 14 days before the first dose and ending 30 days after the last dose of study interventions administration, with the exception of flu vaccines or Coronavirus disease 2019 vaccine.

15. Administration of long-acting immune-modifying drugs (e.g., infliximab) at any time during the study period.

16. Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting 3 months before the administration of the first dose of study interventions or planned administration during the study period.

17. 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(s). For corticosteroids, this will be prednisone equivalent >=20 mg/day for adult participants. Inhaled and topical steroids are allowed.

    Prior/Concurrent Clinical Study Experience:

18. 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 (vaccine and drug).

    Other Exclusions:

19. Pregnant or lactating female.

20. Female planning to become pregnant or planning to discontinue contraceptive precautions.

21. History of/current chronic alcohol consumption and/or drug abuse. This will be decided at the discretion of the Investigator.

22. Any study personnel or their immediate dependents, family, or household members.

Study Sponsor will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/gsk-patient-level-data-sharing-july2025.pdf

Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or asset(s) with development terminated across all indications.

Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months, but an extension may be granted, when justified, for up to 6 months.