The world’s second-deadliest Ebola outbreak just ended.

Nature has some good news about an infectious disease – the outbreak that had killed 2,000 people in the Democratic Republic of Congo appears to be over, thanks to a new vaccine:

“We are extremely proud to have emerged victorious over an epidemic that has lasted a long time and caused a lot of damage to our population,” said Jean-Jacques Muyembe Tamfum, a co-discoverer of Ebola and the director of the National Institute for Biomedical Research in Kinshasa, at a press briefing.

After the outbreak was declared in August 2018, the virus infected at least 3,470 people, killing 66% of them. That makes it the world’s second-largest outbreak of the haemorrhagic disease, after the 2014–16 West Africa epidemic, which killed more than 11,000 people. Experts say that the northeastern epidemic — which mainly affected North Kivu and Ituri provinces — was one of the most complex health emergencies the world has ever seen, because it occurred in a region of the DRC plagued by 25 years of war and political instability.

This was the first Ebola outbreak in which a vaccine for the virus was widely deployed. The vaccine, made by drug company Merck of Kenilworth, New Jersey, and first tested during West Africa epidemic, was given to more than 300,000 people who had been in close proximity to people with Ebola, and their contacts. More than 80% of people who were vaccinated didn’t end up with the disease, said Muyembe, and those who did had relatively mild cases.

A clinical trial conducted during the outbreak also found that two antibody-based drugs, called mAB114 and REGN-EB3, reduced deaths dramatically among people who were hospitalized soon after being infected. These were then given to all consenting patients in Ebola treatment centres in northeastern DRC.

Another key to success, said Muyembe, was local leadership.