Ebola outbreak in Congo nears 10,000 confirmed cases as first vaccine trial begins

The Ebola outbreak in the Democratic Republic of the Congo reached 9,964 confirmed cases and 4,851 related deaths as of October 25, according to the European Centre for Disease Prevention and Control, which based the figures on data through October 24. The outbreak is caused by Bundibugyo virus and has been under way in the country since May.

The World Health Organization declared the outbreak on May 15. In its October 23 update, the agency called it the largest Ebola disease outbreak ever recorded in the DRC, regardless of virus species.

Where the cases are

WHO reported 9,704 confirmed cases in the DRC as of October 20, including 4,687 deaths and 2,595 recoveries, a crude case fatality ratio of 48.3 percent. Since its October 8 update, the agency counted 976 new confirmed cases and 482 deaths. Of those deaths, 307 occurred in communities and 175 in treatment centers.

Cases have been confirmed in 66 health zones across eight provinces, and 50 of those zones reported cases in the past 21 days. Ituri, the epicenter, accounts for 7,040 cases and 3,271 deaths. Nord-Kivu has 2,146 cases and 1,199 deaths, a fatality ratio of 55.9 percent, the highest of any province. Haut-Uélé has 421 cases and 183 deaths, and Tshopo has 76 cases and 27 deaths.

WHO said 30,130 contacts were under follow-up across six provinces. The follow-up rate was 79.7 percent, below the agency’s 95 percent target. Only Bas-Uélé and Sud-Ubangi met the target.

Cases outside Congo

Five countries have reported cases: the DRC, Uganda, France, Kenya and Nigeria. ECDC states that the outbreak in Uganda has ended.

In Kenya, the index case was an adult man who traveled from the DRC through Uganda and arrived in Nairobi on October 3, WHO reported. He died on October 5, and the Ministry of Health announced the confirmed case on October 6. The eight secondary cases form a single cluster of four family members and four health and care workers. All were in quarantine when symptoms began. ECDC lists nine confirmed cases and two deaths in Kenya as of October 25, with the last case reported on October 20 and the second death on October 23. WHO said all 135 contacts were traced and quarantined, and that 709,093 travelers had been screened as of October 22.

Nigeria confirmed one case on October 20 in Abuja, in a patient who had traveled from Uganda. According to ECDC, symptoms began on October 7, the patient sought care on October 11, and 53 contacts have been identified. Investigations are continuing.

ECDC reported four cases linked to the DRC outbreak that were medically evacuated or imported into the European Union and European Economic Area since May. Two patients went to Germany, one to the Netherlands, and one was reported in France in July. All four were health care or humanitarian workers in affected areas of the DRC. ECDC rates the likelihood of infection as low for people in the EU and EEA who live in or travel to affected areas, and very low for people living there.

Vaccine trial begins

WHO said the TUMAINI trial launched on October 23, with the first participants enrolled in Bunia. It is a pivotal Phase 2/3 trial of vaccine candidates against Bundibugyo virus. WHO states that no approved vaccines or specific treatments exist for the disease, and that care relies on supportive treatment.

In August, WHO and the African Union’s public health agency announced an allocation of 70,000 doses of Ervebo from the global Ebola vaccine stockpile. Twenty thousand doses were designated for a Phase 3 trial and 50,000 for frontline and health workers. Ervebo is licensed for Ebola virus disease caused by Zaire ebolavirus, not Bundibugyo. The release states: “It is not known whether Ervebo may be protective against the Bundibugyo virus in humans.” It adds that early laboratory and animal data suggest it may offer some protection.

Travel guidance

WHO assessed the risk as very high for the DRC and high for countries sharing land borders with it as of August 14, and low for the rest of the African region and globally. The agency said it is revising that assessment. It advises against restricting travel to or trade with affected countries. Temporary recommendations issued on August 24 call for coordinated control, cross-border collaboration and sustained surveillance.

WHO notes that fruit bats are suspected natural reservoirs of the virus. The incubation period is 2 to 21 days, and patients are not infectious before symptoms begin. Fatality ratios were about 30 percent in Uganda in 2007 and 50 percent in the DRC in 2012.