Phase I, Randomized, Double-blinded, Placebo-Controlled Dose De-escalation Study to Evaluate Safety and Immunogenicity of Alum Adjuvanted Zika Virus Purified Inactivated Vaccine (ZPIV) in Adults in a Flavivirus Endemic Area

This study is randomized, double-blinded, placebo-controlled, Phase 1, dose de-escalation study to evaluate the safety, reactogenicity, and immunogenicity of Alum Adjuvanted Zika Virus Purified Inactivated Vaccine (ZPIV) administered to healthy male and non-pregnant female adult subjects. This study will enroll 90 healthy male and non-pregnant female subjects between the ages of 21 and 49 and will be conducted at Ponce Medical School Foundation, Inc.-CAIMED in Ponce, Puerto Rico. The duration of each subject's participation is approximately 26 months from recruitment through the last study visit. The entire study is expected to take approximately 49 months to complete. Two dose levels will be evaluated. Each subject will receive either placebo or 5 mcg (Group 1) or 2.5 mcg (Group 2) of ZPIV administered by intramuscular (IM) injection on Days 1 and 29. Solicited local and systemic reactogenicity data will be collected from all subjects through Day 8 after each vaccination. All subjects will be monitored for occurrence of unsolicited adverse events until 28 days after the second vaccination. The study will consist of a screening period of up to 28 days, a vaccination period in which subjects will receive a prime dose of vaccine on Day 1 followed by a boost on Day 29, and a follow-up period of 24 months post boost vaccination. Primary objectives are: 1) Assess the safety and reactogenicity of a homologous prime boost regimen of ZPIV given at two different dose levels. 2) Compare the safety and reactogenicity of ZPIV after each vaccination, between dosage groups, and by pre-vaccination flavivirus immune status.