The purpose of this Phase 1 study is to describe the safety, tolerability and immunogenicity of two doses of purified inactivated Zika virus vaccine (PIZV) given 28 days apart.

Three different vaccine doses containing different protein concentrations (2, 5, or 10 micrograms [mcg]) each, will be given as a 2 dose schedule to flavivirus naive and primed healthy adults.

271 participants will be followed for 7 days post each dose for tolerability and up to 6 months post-dose 2 for safety. Immunogenicity assessment will be performed at 28 days post each dose and 6 months post-dose 2.

In addition, the selected dose group and control group will be followed till 24 months post-dose 2 for safety and persistence of immunity.

Results

On May 18, 2021, the Lancet published the results of this phase 1 study.

TAK-426 was well tolerated, with an acceptable safety profile, and was immunogenic in both flavivirus-naive and flavivirus-primed adults. Based on the safety and immunogenicity profiles of all TAK-426 doses assessed, the 10 μg TAK-426 dose was selected for further clinical development.