Johnson & Johnson has begun clinical trials for an Ebola vaccine in Sierra Leone.
The vaccine regimen is part of a new study being conducted in that nation's Kambia district, where some of the country's most recent Ebola cases have been reported.
More than 11,000 people have died from the Ebola virus since the latest outbreak emerged in late 2013, nearly all of them in West Africa in and around Sierra Leone.
There is currently no licensed vaccine, treatment or cure for Ebola.
The Johnson & Johnson study, in development at subsidiary Janssen Pharmaceutical Cos., will evaluate safety and immune response within Sierra Leone's general population.
The company said Friday 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 U.S., Europe and Africa as part of the accelerated development plan to prevent Ebola outbreaks.