Immunogenicity and Safety of Tetravalent Dengue Vaccine (TDV) at the End of Shelf Life in Healthy Adults

The purpose of this study is to evaluate the safety and immune response of a naturally aged lot of tetravalent dengue vaccine (TDV) in healthy participants, aged 18 to 60 years, in non-endemic country(ies) for dengue.

The vaccine being tested in this study is tetravalent dengue vaccine (TDV). The primary objective of this study is to evaluate the immune response and safety of a naturally aged (\>12 months stored at 2°C to 8°C) lot of TDV in a healthy adult population in country(ies) non-endemic for dengue. The assessment of a naturally aged lot of TDV in this clinical trial will provide an important contribution to data on TDV stability throughout the shelf life of the product.

The study will enroll approximately 200 participants. Participants will be enrolled to the one treatment group:

Tetravalent Dengue Vaccine (TDV)

All participants will receive subcutaneous (SC) injection on Day 1 (Month 0) and Day 90 (Month 3).

This multi-center trial will be conducted in the United States. The overall time to participate in this study is 9 months. Participants will make multiple visits to the clinic including a final visit at Day 270 (Month 9).

Eligibility Criteria:
Inclusion Criteria:

1. Participants who are in good health at the time of entry into the trial as determined by medical history, physical examination (including vital signs), and the clinical judgment of the investigator.
2. Participants who sign and date a written informed consent form and any required privacy authorization prior to the initiation of any trial procedures, after the nature of the trial has been explained according to local regulatory requirements.

Exclusion Criteria:

1. Participants with a clinically significant active infection (as assessed by the investigator) or body temperature ≥38°C (≥100.4°F) within 3 days of the intended date of vaccine administration
2. Known or suspected impairment/alteration of immune function, including:

   1. Chronic use of oral steroids (equivalent to 20 mg/day prednisone ≥12 weeks and/or ≥2 mg/kg body weight/day prednisone ≥2 weeks) within 60 days prior to Day 1 (Month 0) (use of inhaled, intranasal, or topical corticosteroids is allowed).
   2. Receipt of parenteral steroids (equivalent to 20 mg/day prednisone ≥12 weeks and/or ≥2 mg/kg body weight/day prednisone ≥2 weeks) within 60 days prior to Day 1 (Month 0).
   3. Administration of immunoglobulins and/or any blood products within the 3 months prior to Day 1 (Month 0) or planned administration during the trial.
   4. Receipt of immunostimulants within 60 days prior to Day 1 (Month 0).
   5. Immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within 6 months prior to Day 1 (Month 0).
   6. Known Human Immunodeficiency Virus (HIV) infection or HIV-related disease.
   7. Hepatitis C virus infection.
   8. Genetic immunodeficiency.
3. With Body Mass Index (BMI) greater than or equal to 35 kg/m\^2(=weight in kg/height in meters\^2).
4. Participants who have known hypersensitivity or allergy to any of the vaccine components.
5. Previous and planned vaccination (during the trial conduct), against any flavivirus including dengue, Yellow Fever (YF), Japanese Encephalitis (JE) viruses or tick-borne encephalitis.
6. Previous participation in any clinical trial of a dengue or other flavivirus (e.g., West Nile \[WN\] virus) candidate vaccine, except for participants who received placebo in those trials.
7. With a current or previous infection with a flavivirus such as dengue, Zika, YF, JE, WN fever, tick-borne encephalitis or Murray Valley encephalitis and participants with a history of prolonged (≥1 year) habitation in a dengue endemic area.
8. Participants with any history of progressive or severe neurologic disorder, seizure disorder or neuro-inflammatory disease (e.g., Guillain-Barré syndrome).
9. Participants with history of substance or alcohol abuse within the past 2 years.
10. Participants who have any serious chronic or progressive disease according to judgment of the Investigator (e.g., neoplasm, insulin dependent diabetes, cardiac, renal or hepatic disease).