The U.S. Food and Drug administration has approved for the first time in the United States a vaccine for the prevention of the deadly Ebola virus, the agency announced Thursday.

The vaccine, Ervebo, was developed by Merck and protects against Ebola virus disease (EVD) caused by Zaire ebolavirus in people 18 and older, the FDA said in a statement.

Cases of EVD in the US are very rare and have generally occurred when people already infected with the virus have traveled into the country or when health care workers have become infected treating those sickened by EVD.

“While the risk of Ebola virus disease in the U.S. remains low, the U.S. government remains deeply committed to fighting devastating Ebola outbreaks in Africa, including the current outbreak in the Democratic Republic of the Congo,” Anna Abram, FDA Deputy Commissioner for Policy, Legislation, and International Affairs, said in a press release.

Secretary of Health and Human Services, Alex Azar, called the new vaccine “a triumph of American global health leadership.”

The Zaire strain of the Ebola virus has caused more than 2,000 deaths in the current outbreak in the eastern DRC, and more than 11,000 deaths during an outbreak in 2014 in West Africa.

Ebola virus is highly contagious and transmitted through direct contact with blood, body fluids and the tissue of infected wild animals or people. It’s also transmitted through surfaces and materials that have come into contact with an infected person or animal.