Africa CDC to Use Existing Ebola Vaccine Against New Strain in DRC Outbreak
African health authorities will deploy a vaccine developed for the Zaire ebolavirus strain to combat the current Bundibugyo strain outbreak in eastern Democratic Republic of Congo, citing evidence that the shot prevents deaths. The outbreak is spreading at an unprecedented rate, prompting investigations into possible viral mutation.
The African Centres for Disease Control and Prevention (Africa CDC) has announced plans to use an existing Ebola vaccine targeting the Zaire strain to address the ongoing outbreak caused by the distinct, fast-spreading Bundibugyo strain. The epicenter of the outbreak is in the eastern part of the Democratic Republic of Congo (DRC).
Jean Kaseya, the director general of Africa CDC, told reporters during a videoconference on Thursday that limited testing so far suggests the vaccine eliminates deaths, even if it does not always prevent symptoms. He emphasized that the virus is spreading six to eight times faster than any recorded outbreak in the past, prompting Africa CDC and the World Health Organization to launch research into a possible mutation or other abnormality.
According to the latest data, 3,973 confirmed cases had been reported as of Tuesday, with authorities estimating the total at around 4,000. Confirmed deaths stand at 1,801. The outbreak, declared only in mid-May, is already the second-largest on record. Compared to the West Africa outbreak of 2014-2016, the current strain is causing deaths six times faster.
Kaseya noted that cases have now been logged in 51 health zones, up from nine in May. He highlighted concerning contact tracing ratios: during the deadliest Zaire strain outbreak between 2018 and 2020, one patient was identified from every 57 contacts; in Uganda, one from every 41 contacts; but in the current DRC outbreak, there is one confirmed case for every 10 contacts. He stated that in the hardest-hit city of Bunia and the Ituri region, everyone should be considered a potential contact.
The Bundibugyo strain has historically been rare, with no recognized vaccines or treatments. However, medical experts have begun work on a new vaccine. Kaseya said that in limited testing, people vaccinated against the Zaire strain experienced some symptoms but "we saw zero deaths among people who are vaccinated," indicating a level of protection. Authorities also plan to expand the use of the antiviral drug remdesivir, which neighboring Uganda used successfully to treat 20 cases, with only two deaths.
Meanwhile, near the DRC capital Kinshasa, more than 300 people on a river barge are being screened after a passenger died with Ebola-like symptoms. A mobile laboratory was deployed to the vessel in Maluku. Kaseya said the barge had come from Mongala province, where no Ebola cases have been reported, contradicting earlier reports that it originated from the affected Tshopo province.
