Ebola 2018 – Implications for travel health advice and relevance for travel medicine

Since 1976, in more than 40 recorded outbreaks to date, Ebola virus disease (EVD) has dramatically affected the human population across the Central African region and adjacent areas. The large West African outbreak (2013–2015) was a game changer in many aspects, not only with regard to geographical location and the number of patients and deaths, but also in terms of the international community’s response it finally triggered; albeit belatedly so. The progress made in our epidemiological and clinical understanding of the disease was immense, as well as advances in the development of an effective vaccine (e.g. rVZV-ZEBOV), specific therapeutic options (e.g. monoclonal antibodies, convalescent whole blood), and candidates for post-exposure prophylaxis (e.g. Favipiravir) [ ].

As of June 18, 2018, 36 completed trials, seven active and not recruiting, and seven recruiting Ebola vaccine studies are registered on ClinicalTrials.gov . The only study that has been able to provide data on clinical efficacy is the Ebola Ça Suffit vaccination trial in Guinea. This open-label, cluster-randomised trial evaluated vaccine effectiveness in case contacts, where clusters of contacts of Ebola cases were randomised for immediate or delayed vaccination with the recombinant, replication-competent, vesicular stomatitis virus-based vaccine expressing the glycoprotein of a Zaire Ebolavirus (rVSV-ZEBOV). Although the authors estimated the vaccine efficacy to be 100% (95% CI 68·9–100, p=0·0045) in individuals vaccinated in the immediate group compared with those eligible and randomised to the delayed group, the extent of this efficacy has been debated. A report by the US National Academies of Sciences, Engineering, and Medicine stated that “the results suggest that the vaccine most likely provides some protection to recipients—possibly ‘substantial protection,’ as stated in the final report. However, we remain uncertain about the magnitude of its efficacy”