Mass vaccinations and local lockdowns under way as Ebola outbreak spreads in DRC

Health officials in the Democratic Republic of the Congo have begun mass vaccinations and imposed local movement restrictions as an outbreak of the Zaire ebolavirus spreads through Kasai province, officials said.

The World Health Organization said vaccination is being offered to people known to have been exposed to the virus and to front-line health workers after the number of confirmed cases more than doubled in the past week, rising from 28 to 68. The outbreak, declared earlier this month, has resulted in at least 16 deaths, including four health-care workers.

An initial shipment of 400 doses of the Ervebo vaccine — an FDA-approved vaccine used only during outbreaks and effective against the Zaire ebolavirus species — has been dispatched to Bulape, a current hotspot in the Mweka territory, local authorities and the WHO said. The WHO’s International Coordinating Group on Vaccine Provision approved an additional 45,000 vaccines, increasing the DRC’s existing stockpile of roughly 2,000 doses. Additional supplies are expected to arrive in the coming days.

Treatment courses of the monoclonal antibody therapy Mab114, marketed as Ebanga, have been sent to treatment centers in Bulape. Ebanga and Inmazeb are the two monoclonal antibody treatments approved by the U.S. Food and Drug Administration for Ebola; Ebanga blocks the viral glycoprotein that allows the virus to attach to and enter host cells.

Local officials have restricted movement in affected areas and set up checkpoints along territorial borders to limit travel, and some communities have been placed under confinement to prevent further spread, authorities said. Francois Mingambengele, administrator of Mweka territory, described the situation to Reuters as a crisis, saying cases are multiplying.

The first confirmed case linked to the current outbreak was a pregnant woman who visited Bulape General Reference Hospital on Aug. 20 with fever, bloody stool, abnormal bleeding and weakness. She died five days later of organ failure; testing on Sept. 4 confirmed Ebola as the cause.

Ebola virus disease is transmitted through contact with the blood or body fluids of an infected person, contaminated objects, or infected animals such as bats or primates. Symptoms typically include fever, headache, muscle pain, vomiting, diarrhea, abdominal pain and unexplained bleeding or bruising. Without treatment, Ebola can cause severe disease with mortality rates that can reach as high as 90 percent; the Zaire ebolavirus species, which is responsible for the current outbreak, has historically produced case fatality rates ranging roughly from 36 to 90 percent.

Ebola has been detected in the DRC since 1976. The current outbreak is the country’s 16th overall and the seventh in Kasai province. Prior outbreaks in eastern DRC in 2018 and 2020 each resulted in more than 1,000 deaths, and the largest global epidemic occurred in West Africa from 2014 to 2016 with more than 28,600 reported cases.

The WHO said the Ervebo vaccine is "safe and protects against the Zaire ebolavirus species, which has been confirmed as the cause of the ongoing outbreak." Vaccination campaigns in the DRC have historically used ring vaccination strategies that target contacts of confirmed cases and front-line workers rather than offering vaccines to the general public.

Earlier this year, Uganda experienced its own outbreak of a separate Ebola virus species, the Sudan virus, which caused a severe form of hemorrhagic fever before being declared over in April. In the United States, two suspected cases were investigated in February after patients who had recently traveled from Uganda showed Ebola-like symptoms; subsequent tests ruled out Ebola in those cases.

Health authorities in the DRC and international partners are continuing case finding, contact tracing, vaccination of contacts and health-care personnel, and provision of therapeutics. Officials have urged residents in affected areas to cooperate with containment measures and to seek medical care promptly if they develop symptoms consistent with Ebola.

The WHO and DRC health authorities did not provide an immediate estimate for how long vaccination and movement restrictions might continue, saying the response would be guided by evolving case counts and patterns of transmission.