The vaccine regimen is part of a new study being conducted in Sierra Leone's Kambia district, where some of the country's most recent Ebola cases have been reported.
The study, in development at subsidiary Janssen Pharmaceutical Cos, will evaluate safety and immune response within Sierra Leone's general population.
The company said today that the first volunteers have received the initial dose.
Johnson & Johnson, based in New Brunswick, New Jersey, said that there are separate studies being conducted in the US, Europe and Africa as part of the accelerated development plan to prevent Ebola outbreaks.