The ongoing Ebolavirus disease (EVD) outbreak in North Kivu province, Democratic Republic of the Congo (DRC), is the first to use experimental vaccinations and drug therapies from the start of the outbreak.
Ebolavirus infection is now a candidate disease under the World Health Organization’s Monitored Emergency Use of Unregistered and Investigational Interventions (MEURI), and compassionate use of several investigational agents to prevent and treat EVD in the current outbreak has been approved by both the WHO, and the health authorities in the DRC.
Currently, three experimental agents are being administered in treatment facilities in the North Kivu cities of Beni, Butembo, Katwa, and Mangina for patients with laboratory confirmed EVD. Two of these medications are antibody therapies: single mAb114 therapy, and a cocktail of REGN-EB3 with the previously publicised ZMapp. The third is a small-molecule inhibitor drug, Remdesivir. This is not the first time that a drug has been used without formal clinical approval to treat Ebola patients.
ZMapp was previously used during the West Africa EVD outbreak in 2014-2016; however statistical shortfalls meant that the drug’s efficacy could not be properly evaluated, when comparing it to the existing standard of care across Liberia, Sierra Leone, Guinea and the United States (n=72). Therefore, the use of these new treatments in the DRC present an opportunity for patients to receive potentially life-saving treatments while investigators are able to obtain a larger-scale evaluation of clinical effectiveness.
As well as EVD treatments, a candidate vaccine is currently undergoing large-scale field trials in the DRC. Recombinant Vesicular Stomatitis virus-vectored vaccine for Ebolavirus disease (rVSV-ZEBOV) has shown protective markers in 100% of those vaccinated, and a 2017 study on the West Africa outbreak reported that for individuals vaccinated immediately after contact with an infected person, the vaccine was 100% effective in preventing these individuals from contracting EVD (n=3,796).
As of 13 July 2019, over 160,000 people have received this vaccine in the DRC, including front line health workers and at-risk individuals. It is yet to be determined how effective it will be, as previous studies note that the longer between contact with an infected individual and receiving the vaccine, the less effective the vaccine is. Because of this, the vaccine is primary being used in a ring-vaccine strategy wherein the contacts of infected individuals are rapidly vaccinated and monitored. This approach is highly effective in stopping disease transmission; however, the approach has led to some community resistance with individuals expressing concern that only some people are being given the vaccine instead of all in the community.
Unfortunately, current logistics and resources (including a limited vaccine supply) have prevented large-scale whole-community vaccination approaches. A second experimental vaccine has been offered for use in combating this outbreak; however, the vaccine requires two doses and the DRC has blocked its use as they believe that delivering two doses of vaccine to each individual is not logistically feasible and the presence of two different vaccines could further strain community trust.
These issues further demonstrate the necessity of evidence-based aid and of open communication between researchers, aid workers, and communities in order to enable rapid delivery of effective medical aid while facilitating community uptake and engagement.
