This is a Phase 1 study to assess safety and tolerability of a single subcutaneous dose of Dengusiil in healthy adults of 18 to 45 years of age. In this study, immune response to Dengusiil will also be assessed over a period of 6 months and vaccine viremia will also be assessed over a period of 12 days after administration of vaccine.

Inclusion Criteria:

1. Healthy adults aged 18-45, men, or women.

2. Seronegative for Dengue NS1 and IgM at screening indicating no current dengue infection

3. Seronegative for dengue IgG at screening

4. Participants who are willing to comply with the requirements of the study protocol and attend scheduled visits.

5. Participants who give written informed consent approved by the Human Research Ethics Committee (HREC) governing the site.

6. Participants must have the laboratory parameters within normal range.

7. Participants with Body Mass Index (BMI) between 18 to 30 (both inclusive)

8. Satisfactory baseline medical assessment as assessed by physical examination and normal laboratory values or minor variations those are acceptable for study entry.

9. Participants should agree to not:

   1. donate blood for the purpose of blood transfusion
   2. donate an organ for the purpose of transplantation
   3. to share needles with other people
   4. allow their blood to come in contact with another person's mucous membranes for 84 days post-vaccination.

Exclusion Criteria:

1. Previous dengue vaccination.
2. Presence of acute infection in the preceding 14 days or presence of a temperature ≥ 38.0°C, or acute symptoms of infection greater than of "mild" severity on the scheduled date of first dosing
3. Evidence of any other significant active haematological disease, or having donated > 450 mL of blood within the past three months.
4. Evidence or history of substance abuse including alcohol or previous substance abuse within the last year.
5. Participation or planned participation in a study involving the administration of an investigational compound within the past one month or during this study period.
6. Planned administration of any vaccine not foreseen by the study protocol 4 weeks before and after dosing.
7. History of allergic disease, allergic reactions or known hypersensitivity to any component of the study vaccines.
8. Confirmed or suspected immunosuppressive or immune-deficient condition.
9. A family history of congenital or hereditary immunodeficiency.
10. Chronic administration (defined as more than 14 days) of immune-suppressants or other immune-modifying agents within six months prior to administration of study vaccine. (For corticosteroids, this means prednisone, or equivalent, ≥ 0.5 mg/kg/day; topical or inhalable steroids are allowed.)
11. Laboratory confirmed infection with either hepatitis B virus (HBs Ag positive), hepatitis C virus (anti-HCV positive), or human immunodeficiency virus (HIV) at screening.
12. Known bleeding disorders.
13. Administration of immunoglobulins and/or any blood products within the three months preceding the administration of study vaccines or planned administration during the study period.
14. Women who are pregnant, breast-feeding, or considering becoming pregnant.
15. Any other condition, which in the opinion of the investigator, might interfere with the study objectives, jeopardize the safety or rights of the participant or making it unlikely the participant could complete the protocol.