The Democratic Republic of Congo has received its first shipment of more than 16,000 doses of an Ebola vaccine as authorities race to contain an outbreak that has killed more than 2,500 people and is spreading rapidly across six provinces.

A batch of 16,520 doses of the Ervebo vaccine arrived in Kinshasa late Friday, Health Minister Samuel Roger Kamba said, with more than 50,000 additional doses expected by Monday.

“These doses would strengthen the government’s response to Ebola and contribute to the protection of populations, with the support of our partners,” Kamba told reporters at Kinshasa airport.

The World Health Organization said Thursday that 70,000 doses of Ervebo would be supplied to Congo from the global Ebola vaccine stockpile. Of those, 20,000 doses will be used in a Phase 3 clinical trial examining whether the vaccine can protect against the strain responsible for the current outbreak, while 50,000 will be administered to frontline and health workers.

The vaccine, developed by Merck and manufactured in Germany, is licensed and recommended for outbreaks caused by the Zaire strain of Ebola. The current outbreak, however, is being driven by the Bundibugyo strain, for which no vaccine or specific treatment has yet been approved.