Tuesday, August 21, 2018

Another Ebola Outbreak In The DRC

Image courtesy of Nortumbria University/PHYS.ORG


--Ebola is back in the Democratic Republic of Congo (DRC), closely following the outbreakin northwestern Equateur province, which was declared over on July 24th 2018; and the World Health Organization (WHO) is now "more worried", and has characterized the situation as: "We are on an epidemiological precipice." The current outbreak, the tenth in the DRC, is occurring in the Mangina health area. As of August 18th the WHO reported 90 cases (63 confirmed and 27 probable), with an additional 25 suspect cases under investigation, and 49 deaths. Nine of the confirmed cases are healthcare workers. While thus far, these two outbreaks "do not appear to be related", this situation is instructive in terms of reconsidering the criteria for declaring the end of an Ebola outbreak.

The reported cases are from five health zones in North Kivu, and one health zone in Ituri, and all are linked to the "outbreak epi-center" in Mangina. North Kivu and Ituri are two of the most populated provinces in the DRC, plagued by conflict and insecurity, with over one million internally displaced people and migration of refugees to neighboring countries; and share borders with Uganda and Rwanda. It is the first time that an Ebola outbreak has occurred in a densely populated active conflict zone.

This pattern of spread, in this context, is a perfect recipe for an epidemiological nightmare, and the forthrightness and transparency of the WHO in sounding the alarm early, should help to mobilize much-needed resources and adequate governmental response in that region and internationally. A major challenge is this regard, is the fact that Ebola Virus Disease is no longer a novel threat worldwide, like it was portrayed and experienced during the 2014 outbreak in West Africa. Rather, it may now be perceived by many as a familiar threat that can be managed, especially given recent publications suggesting that there is an effective Ebola vaccine. Such public perception must be properly addressed.

All Ebola vaccines and treatments being used are strictly experimental, and there is no clear and convincing empirical evidence of the effectiveness of any of these interventions, at this time. Any claim of effectiveness is based on theory and inference, at best. In particular, according to members of an international Ebola research consortium: "The rVSV-ZEBOV experimental vaccine, which has been deployed in the DRC, is the only candidate with some clinical efficacy data." Note that clinical efficacy refers to the extent to which an intervention produces expected outcomes under highly controlled or ideal circumstances, whereas clinical effectiveness is a pragmatic measure of how beneficial an intervention is in real-world clinical settings.

In closing, let me reiterate what I wrote on May 14th: "Indeed, if a worse-case scenario is averted in this outbreak, it will be primarily because of old-fashioned epidemiology, and not the use of the experimental vaccine. While a multi-pronged approach should be employed, the emphasis must be on ongoing and comprehensive surveillance, contact tracing, isolation and quarantining, and of course, culturally sensitive health education, and the provision of supportive therapy. As well, there must be sensible travel restrictions, and assessment of travel history."

Rossi A. Hassad, PhD, MPH, is an epidemiologist, and professor at Mercy College in Dobbs Ferry, N.Y. He is a member of the American College of Epidemiology, and a Fellow and Chartered Statistician of the Royal Statistical Society.
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