The results offer hope of better protection against the disease that ravaged West Africa in 2014, killing more than 11,000 people.
The experimental vaccine was given in 2015 to people in Guinea who were in contact with patients who had recently confirmed cases of Ebola.
A few months after the early trials, the World Health Organization said the preliminary results were an "extremely promising development."
While the study's participants were initially randomized, the process was stopped after initial results in order to get the vaccine to those in need.
The trial involved more than 11,000 people, according to the WHO, which led the trial in conjunction with Guinea's Ministry of Health.
A total of 5,837 people were given the rVSV-ZEBOV vaccine, and none had a recorded case of Ebola after 10 days or longer, the study says.
Among people who were not immediately given the vaccine, there were 23 cases.
Some people who had the vaccine reported headaches, fatigue and muscle pain. Two patients had serious reactions, including one who had an allergic reaction.