DR Congo Ebola toll passes 5,300 as strain defies vaccines

The death toll from the Ebola outbreak centred on the Democratic Republic of the Congo has passed 5,300, the Africa Centres for Disease Control and Prevention said on Monday, cementing it as the deadliest outbreak of the virus on record. According to Al Jazeera, the Africa CDC put the total at 5,376 dead: 5,372 in the DRC and two each in Kenya and Uganda.

The figures deserve a small caveat, of the kind official statements excel at burying. Africanews reported that the sharp rise in recorded deaths reflected a retrospective adjustment between local data teams and the outbreak management team in Ituri province, rather than a single-day surge. The underlying trend, though, is bad enough: the DRC's National Institute of Biomedical Research counted 10,414 confirmed cases as of October 30, with a case fatality rate of 51.6 percent.

The culprit is the Bundibugyo strain, for which no approved vaccine or treatment exists. Health workers can only manage symptoms. Clinical trials have begun in recent weeks with the Ervebo vaccine, proven against the more common Zaire strain, though whether it works against this one remains an open question. The DRC declared the outbreak — its 17th and largest — in mid-May.

What will worry epidemiologists most is a single figure: according to the Africa CDC, about 80 percent of new cases are arising outside the chain of monitored contacts. In plain English, four out of five infections come from transmission routes health authorities cannot see. That is how outbreaks outrun contact tracers.

The virus has crossed borders repeatedly. Uganda recorded 20 cases, almost all in travellers from the DRC, before being declared Ebola-free in August; Kenya saw its first-ever cases in October, with nine infections and two deaths. Nigeria tested two suspected cases in its northeast and found both negative, though Abuja reported an imported case in October, its first in more than a decade. France recorded a single case in July involving a health worker returning from the DRC. Wide World News tracked the spread to neighbouring states earlier this autumn.

The next markers to watch are the Ervebo trial results and the Africa CDC's weekly situation reports. Until one produces a vaccine that works, or the other shows transmission chains closing, the numbers will keep being revised — politely, retrospectively, and upwards.