Rare Ebola Strain With No Vaccine Linked to 87 Congo Deaths

(Bloomberg) -- A rare strain of Ebola with no approved vaccine or treatment circulated undetected for weeks in conflict-hit northeastern Democratic Republic of Congo before killing at least 87 people.The first case developed symptoms on April 24, creating a four-week detection delay that enabled extensive uncontrolled community transmission, Africa Centres for Disease Control and Prevention Director-General Jean Kaseya said in an online briefing Saturday. About 336 potential cases have been reported, mainly in Mongbwalu and Rwampara health zones in Ituri province near the Ugandan border, with additional possible infections in the provincial capital Bunia, Kaseya said. Four deaths have been confirmed among laboratory-positive cases.Laboratory testing by the National Institute for Biomedical Research in Kinshasa confirmed the outbreak is caused by the Bundibugyo strain. The virus has caused only two previous known outbreaks: in Uganda in 2007 and eastern Congo in 2012. The deaths and suspected cases in this cluster have already exceeded those of the previous two outbreaks of this type combined.“Every single day this region is where we have more than 70% of disease outbreaks in Africa coming from,” Kaseya said. “This is why we need to cover the region, cover the continent, and I am calling upon partners” to support the countries most at risk. Ebola is among the world’s deadliest infectious diseases, killing between roughly a quarter and almost 90% of infected people depending on the virus species and the medical care available. The Zaire strain, discovered in 1976 near the Ebola River in what is now the Democratic Republic of Congo, caused a devastating West African epidemic roughly a decade earlier and has received the most research funding, leading to licensed vaccines and treatments.“Ebola Zaire is the one that got all the attention, for very good reasons,” said Susan McLellan, director of the biocontainment care unit at the University of Texas Medical Branch, in an interview. The development of medical countermeasures, including monoclonal antibodies and vaccines, is less advanced for Bundibugyo, she said.Treatment OptionsAfrica CDC and the World Health Organization convened scientific experts this week to review possible therapies and vaccines and discuss accelerated plans to study their effectiveness, including whether existing vaccines may offer cross-protection against different Ebola strains, said Shanelle Hall, Africa CDC’s principal adviser on management and operations.Health officials are considering four potential Ebola treatments for use under randomized controlled trial protocols in Congo and Uganda, including monoclonal antibodies, Gilead Sciences Inc.’s remdesivir and an oral version of the antiviral, she said.Discussions are ongoing with both governments, though no trials have started yet, Hall said. Laboratory research has suggested the strain may be more susceptible to the antiviral than Ebola Zaire. Several vaccine candidates are also under review. While Merck & Co.’s Ervebo vaccine is being considered, most existing Ebola vaccines were developed for the Sudan and Zaire strains rather than Bundibugyo. Early-stage candidates targeting the Bundibugyo strain from groups including Oxford University and Moderna Inc. are also being assessed.The Ervebo shot remains too expensive for routine use at about $98.60 per dose and also requires ultra-cold storage, complicating deployment in remote areas, Hall said. Work is underway on next-generation Ebola vaccines that would be easier to store, cheaper to produce and potentially protect against multiple Ebola strains, including Bundibugyo.Uganda CaseUganda has also confirmed a Bundibugyo Ebola case in a Congolese patient who traveled across the border for treatment and died in intensive care in Kampala on May 14 after deteriorating with bleeding symptoms. Authorities said the body was transported back to Congo the same evening, highlighting the risk of cross-border transm