Ebola vaccine shows "very impressive" performance in outbreak

Of more than 90,000 people who were vaccinated, only 71 went on to develop Ebola. Fifty-six of those people developed symptoms fewer than 10 days after being vaccinated, suggesting the vaccine had not yet had time to fully protect them. It is believed it takes about 10 days for immune protection to develop after vaccination.

Only 15 people developed Ebola more than 10 days after being vaccinated, the report said. Seven of them were health-care workers. Nearly 29,000 health-care and front-line workers were among the roughly 90,000 vaccinated between last August and March 25, the time period covered by the report.