Safety, Tolerability and Immunogenicity Study of 3 Prime-boost Regimens for Ebola Vaccines Ad26.ZEBOV/MVA-BN-Filo in Healthy Adults, Children and Human Immunodeficiency Virus Positive (HIV+) Adults

This is a randomized, observer-blind, placebo-controlled, parallel-group, multicenter, Phase 2 study evaluating the safety, tolerability and immunogenicity of 3 heterologous prime-boost regimens using Ad26.ZEBOV as prime and MVA-BN-Filo as boost vaccination, administered at 28-, 56- and 84-day (Group 1, 2 and 3 as above) intervals, in healthy adults and elderly participants. A 28- and 56-day (Groups 1 and 2, as above) schedule will be evaluated in HIV-infected participants and in healthy children in 2 age strata. The study consists of a screening phase of up to 8 weeks, a vaccination phase in which participants will be vaccinated at baseline (Day 1) followed by a boost vaccination on Day 29, 57 or 85, a post-vaccination phase and long-term follow-up phase until Day 365. Participants in Cohort 1 substudy (Group 1 and 2) who received Ad26.ZEBOV and MVA-BN-Filo (at selected sites) will receive Ad26.ZEBOV as third vaccination and who received placebo will receive placebo as third vaccination (at least 1 year post prime vaccination). All participants within a cohort will be followed in a blinded manner by the site until the last subject in that cohort has completed the study. This study will be conducted in Africa and the enrollment will take place sequentially in three cohorts: the first cohort will consist of healthy participants (18 - 70 years); the second cohort (2a) will include HIV-infected participants (18 to 50 years) and healthy children 12 to 17 years (cohort 2b); the third cohort will include children aged 4 to 11 years inclusive will be enrolled. Within each cohort, participants will be randomized in a 5:1 ratio to receive active vaccine versus placebo. Safety evaluations will include assessments of adverse events, an electrocardiogram (ECG) for adult participants at screening, physical examination, vital signs (blood pressure, pulse/heart rate, body temperature), clinical laboratory and pregnancy testing. An independent data monitoring committee (IDMC) will be established to monitor data on a regular basis to ensure the continuing safety of the participants enrolled in the study.