Ebola hasn’t goneaway. In fact, the ongoingoutbreak in Africais among the most concerningepidemicsthe organization trying to tame it has ever seen.

“Other than Covid, which affected the whole world, this is the thing that has frightened me the most,” says Nicole Lurie, who has worked for Coalition for Epidemic Preparedness Innovations since 2017 and now serves as executive director for preparedness and response and the US director.

More than 7,000 people have contracted the BundibugyoEbola virusin the Democratic Republic of Congo since May, around half of whom have died, according to government data compiled by the World Health Organization.

“This is the most rapidly growing Ebola outbreak that we’ve seen. It’s probably on pace to be the worst the world has ever seen,” Lurie tells WIRED, “and it’s quite terrifying.”

While health officials were able to end the outbreak in Uganda through contact tracing, isolation, and clinical care, instability in the DRC means cases continue to climb. Millions of people have been displaced by ongoing violence, which has made contact tracing a “struggle,” according to Lurie. Matters have only been made harder by a distrust of outside humanitarian workers, which has made isolating and treating cases difficult. Locals have attacked Red Cross volunteers, destroyed medical equipment including ambulances, anddelayed safe burial teams.

“I don’t think we’re going to be able to bring this to an end without a vaccine,” Lurie says.

Shortly after the first Bundibugyo cases were reported in May, nonprofit CEPI redirected $100 million of internal funding to develop a vaccine. That money helped fund scientists at the Serum Institute of India to manufacture doses of Oxford University’s ChAdOx1 BDBV vaccine at record speed. That and Moderna’s vaccine candidate, also supported by CEPI, have entered safety trials, with efficacy trials expected to start this month.

Though CEPI sees a vaccine as key to ending the epidemic, it’s likely that any trials, which require contact tracing, will still face challenges in the communities. "The thing that worries me is vaccine distrust and mistrust,” says vaccinology and immunology professor Teresa Lambe, who is the lead scientific investigator in the Oxford safety trials. “And even if we get vaccines that are fabulous, will they be used?”

She had been working on a hantavirus vaccine in May following thecruise ship outbreakwhen her phone lit up with a message from a former WHO employee about Ebola that made her swear out loud. She knew the instability in the DRC could make any Ebola outbreak escape control very rapidly, so she pivoted and kick-started her vaccine drive with philanthropic funding even before CEPI set up support.

"Covid was in some ways easier,” reflects Lambe, who says she hasn’t taken a day off since May. “We're not in a lockdown, we're not in a situation where people even know or care about what's going on in the DRC … You're not all pulling in the same direction because day-to-day life continues.”

Global responder organizations have been short of staff since the USwithdrew from the World Health Organizationanddismantled USAIDat the start of President Donald Trump’s second term. Hisadministration’s cuts to foreign aidhave also left responders facing ashortage in basic medical equipmentlike masks, hand sanitizers, and testing gear.

The US State Department didn’t respond to a request for comment.

“CDC teams and partners are strengthening preparedness in the region by supporting surveillance, contact tracing, laboratory diagnostics, infection prevention and control, border health activities, community engagement, and other outbreak containment efforts in coordination with the governments of the DRC, Uganda, and other partners,” Emily Hillard, press secretary for the Department of Health and Human Services, writes in an email. She adds that in the US, the agency is helping provide “enhanced travel screening, clinical and public health guidance, laboratory readiness, and coordination with state and local health departments.”