Health workers in the Democratic Republic of Congo are to begin an immunisation campaign in an attempt to halt the spread of the deadly Ebola virus.
The experimental vaccine proved effective when used in limited trials during the outbreak in West Africa in 2014-16.
At least 25 people are believed to have died in the current outbreak.
Health workers will be among the first to receive the vaccine on Monday.
More than 4,000 doses of vaccine have been shipped to the large port city of Mbandaka, where three cases of the virus have been confirmed since last week and two are suspected. More vaccine is on the way.
Twenty-six Ebola-related deaths have been reported in northwestern DRC since April along with a number of suspected cases.
“Previous outbreaks have demonstrated the importance of a rapid and well-resourced response in order to save lives, but also prevent an exponential increase in the economic cost of a response,” World Health Organization spokesman Tarik Jasarevic said Sunday.
The WHO and Congolese health officials are striving to stop outbreak from moving down river from Mbandaka to Kinshasa, where 10 million people live.
President Joseph Kabila and his Cabinet have increased Ebola emergency response funds to more than $4 million.
The latest Ebola outbreak is the ninth in the DRC since the 1970s.
A 2013 outbreak in West Africa lasted more than two years and killed more than 11,300 people. Most of the victims lived in Guinea, Liberia, and Sierra Leone with other cases scattered as far away as the United States.
Ebola causes internal bleeding, vomiting, and diarrhea and is spread through direct contact with a victim’s bodily fluids. There is no specific treatment.
An outbreak in a densely populated urban area could be catastrophic, experts say.