World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus, PhD, arrived late yesterday in the capital of the Democratic Republic of the Congo (DRC) amid an expanding Ebola outbreak.

Speaking from Kinshasa before traveling to Ituri province, the outbreak’s epicenter, Tedros said the outbreak is very complex but can be stopped and that he wanted the people in Ituri and neighboring North and South Kivu provinces to know “that they are not alone.” Tedros also called for increased international support “so the health workers get the supplies and the protective measures they need.” 

In an update today, the WHO said a total of 906 suspected cases and 223 suspected deaths have been reported in DRC, with 134 cases confirmed, including nine in neighboring Uganda. Eighteen deaths from Ebola have been confirmed across both countries. The outbreak has been caused by a rarer strain of Ebola known as the Bundibugyo virus, which has no approved treatments or vaccines, and is occurring in a region where armed conflict has caused massive refugee movement.

The WHO said challenges in contract tracing and follow-up, insecurity, and inadequate isolation, care, and referral systems for patients are all complicating response efforts, as are community resistance and attacks on health facilities.

“These create additional risks for undetected transmission, disrupt outbreak response efforts, and reinforce the need to strengthen community protection and engagement activities,” the agency said.

At a press conference, an official from the WHO’s High Threat Pathogens Team estimated that the death rate among those confirmed to be infected is 30% to 50%.

“That means up to five out of 10 people are likely to die,” said Anais Legand, MPH.

Kenyan court blocks planned US quarantine facility

In other outbreak news, a court in Kenya has temporarily blocked a US plan to establish a makeshift quarantine facility for up to 50 Americans who’ve been exposed to Ebola, according to media reports. The decision comes a day after US officials said the Kenyan government had agreed to the plan, which has been widely criticized by public health experts.

The plan to build the facility, built by the US military on Laikipia Air Base in Kenya, was challenged by Kenya’s Katiba Institute, which argued that it “raises grave constitutional concerns.” The judge said the field hospital should not operate until the court hears the full case on June 2.

To date, one American, a missionary physician, has been exposed to Ebola in the outbreak. He’s currently being treated at a hospital in Prague, the Washington Post reports.

At a press briefing today, Satish Pillai, MD, MPH, incident manager for the Center for Disease Control and Prevention’s (CDC’s) Ebola response, repeatedly referred questions about the Kenya facility to the US State Department, which he said is the lead federal agency for those efforts.

Pillai said CDC’s efforts are focused on supporting the affected countries and “maintaining readiness here at home” and noted that more than 230 CDC employees are currently supporting the response effort, including 54 who are helping with Ebola screening at four US airports. CDC staff members, a mix of volunteers and commissioned staff, are also on the ground in DRC and Uganda, Pillai said.

Pillai also reiterated that the risk for the United States remains low.

“However, outbreaks like this remind us that infectious diseases don’t respect orders,” he said. “And CDC will continue working with partners to stop transmission at its source, protect affected communities and help ensure the United States remains prepared.”

Recommend treatment, vaccine candidates

The current Ebola outbreak in DRC is the country’s 17th since 1976, when the virus was first discovered. But unlike the Zaire strain, which caused the devastating 2014-16 West Africa epidemic and an outbreak in DRC last year, Bundibugyo has no approved therapeutics or vaccines. In response, the WHO convened meetings of experts to make recommendations on which therapeutic and vaccine candidates should be prioritized.

Yesterday, the WHO issued reports summarizing those meetings. The experts recommended prioritizing three therapeutic candidates for evaluation in patients with confirmed Bundibugyo virus disease: the antiviral remdesivir, which was originally developed for hepatitis C and has been used to treat COVID-19 patients, and the monoclonal antibodies MBP134, developed by Mapp Biopharmaceutical, and Regeneron’s maftivimab. They also suggested investigating a combination of remdesivir and monoclonal antibodies. 

The oral antiviral obeldesivir, developed by Gilead Sciences, was determined to be a priority candidate for postexposure prophylaxis among contacts of confirmed and probable cases, though it was noted that the approach depends on effective contact tracing, which has been a challenge in the current outbreak.

The most promising vaccine candidate identified by the experts was the rVSV Bundibugyo vaccine, developed by the International AIDS Vaccine Initiative. That vaccine, however, would likely need seven to nine months before it would be ready for evaluation in a clinical trial. Another candidate, ChAdOx1 Bundibugyo, developed by Oxford University and the Serum Institute of India, might be ready for assessment in two to three months, but further animal data are needed, the experts said.

The consensus was that a Bundibugyo-specific vaccine would be the preferred option. The evidence for cross-protection from Ervebo, the licensed Ebola vaccine for the Zaire strain, was considered limited and inconclusive.

The WHO said it’s working with the governments of the DRC and Uganda, the Africa Centres for Disease Control and Prevention, and other scientific partners to develop and implement appropriate protocols to evaluate the efficacy and safety of the prioritized candidates.