The candidate vaccine being tested in this study is called PIZV (purified inactivated zika virus vaccine) or TAK-426. This study will look at the safety and immunogenicity of PIZV in healthy participants.~The study will enroll approximately 156 healthy participants in a staggered manner stratified by age groups: Group A (≥18 to <50 years) and Group B (≥50 to <65 years), in a 2-dose Vaccination Period followed by a Booster Period. Participants will be randomly assigned (by chance, like flipping a coin) to either PIZV or placebo in each group and period-which will remain undisclosed to the study observer during the study:~Group A: ≥18 to <50 years~Group B: ≥50 to <65 years~Participants will be randomized into 2:1 to receive placebo or PIZV 0.5 ml intramuscular injection into the middle third of the deltoid muscle, preferably in the non-dominant arm on Days 1 (Visit 1) and 29 (Visit 2). Participants who receive PIZV 0.5 ml in the 2-dose Vaccination Period will be re-randomized to receive placebo or PIZV 0.5 ml in the Booster Period. The seropositivity rate, seroconversion rate, and geometric-mean titers will be measured 28 days post dose 2. Solicited local reactions and systemic adverse events (AEs) will be assessed for 7 days after each vaccination. Unsolicited AEs will be assessed for 28 days after each vaccination and serious AEs (SAEs), AEs of special interest (AESIs), and medically-attended AEs (MAAEs) throughout the entire study period.~This multi-center trial will be conducted in the United States (US). Trial participants will be in this study for 7 to 13 months.
The purpose of this study is to describe the side effects and immune response of a candidate vaccine that might protect against Zika. The vaccine called PIZV (purified inactivated Zika virus vaccine) is given by injection in two doses that are 28 days apart in healthy adults. Participants will receive PIZV or placebo and will be followed for 7 days after each dose and up to 6 months after dose 2. In addition, participants who received only PIZV will receive a booster dose of PIZV or placebo at 6 months after dose 2 and will be followed 12 months after dose 2.