Phase I Trial of Measles Vectored Chikungungya Vaccine

This study is a randomized, double-blinded, Phase 1, placebo- controlled, and dose comparison trial to evaluate the safety, immunogenicity and schedule of MV-CHIK. Two dosage levels (5 x 10\^4 or 5 x 10\^5 TCID50) and 3 immunization schedules (days 1 and 29, days 1 and 85 or days 1 and 169) will be evaluated. The study will have 6 cohorts, each with 30 subjects, 25 of whom will receive study vaccine and 5 of whom will receive placebo. Cohorts 1-3 will receive the low dosage of the lyophilized vaccine product (5 x 10\^4 TCID50) and cohorts 4-6 will receive the high dosage (5 x 10\^5 TCID50) of the lyophilized vaccine product. Each subject will receive two study injections using one of the three dosing schedules outlined above. This study will enroll up to 180 healthy subjects aged 18 to 45 years (inclusive). Subjects will be counseled on the study and will then sign an informed consent prior to any study procedures. Screening will be performed which will include evaluation of medical history, travel history to countries with known CHIKV circulation, medication history, a physical examination and safety laboratory evaluations. Study duration is approximately 22 months. Subject participation duration is approximately 8-13 months. The primary objectives are to evaluate the safety and tolerability of 5 x 10\^4 TCID50 and 5 x 10\^5 TCID50 MV-CHIK and placebo following two consecutive intramuscular injections and to assess the CHIKV serum plaque reduction neutralization test (PRNT50) antibody responses to 5 x 10\^4 TCID50, 5 x 10\^5 TCID50 of MV-CHIK or placebo on day 29 following the first dose. The secondary objectives are to assess the CHIKV serum plaque reduction neutralization test (PRNT50) antibody responses to 5 x 10\^4 TCID50, 5 x 10\^5 TCID50 MV-CHIK and or placebo using three dose schedules (days 1 and 29, days 1 and 85, or days 1 and 169) on day 29 following the second dose, assess CHIKV serum PRNT50 antibody responses to 5 x 10\^4 TCID50, 5 x 10\^5 TCID50 MV-CHIK or placebo on days 15, 85 and 169 following the second dose of vaccine, assess the CHIKV serum ELISA antibody responses to 5 x 10\^4 TCID50, 5 x 10\^5 TCID50 MV-CHIK or placebo on day 29 following the first dose of vaccine and days 15, 29, 85 and 169 following the second dose of vaccine, and to assess the durability of CHIKV serum ELISA and PRNT50 antibody responses to 5 x 10\^4 TCID50, 5 x 10\^5 TCID50 MV-CHIK or placebo on day 85 (Groups 2+5) and day 169 (Groups 3+6) following the first dose of vaccine.