Just last night I read about the new ebola vaccine being 100% effective when given promptly to those who come in contact with an ebola victim. It was tested when a victim was identified in Guinea. The "control group" was also given the vaccine, but 3 wks after exposure. Waiting longer to give the vaccine, however, resulted in more of those in the control group getting the disease, though it still had some efficacy (my understanding of the article, though it was not entirely clear how many were in the control group).
This AM, I read of a case in Sierra Leone which involves about 600 contacts for a newly identified case. A member returned to the village from a larger city to celebrate the end of Ramadan. The article indicated that this victim's contacted would also be treated with the vaccine.
The vaccine was developed in Canada by Merck. Other drug companies like J&J were/are also working on ebola vaccines.