The latest Ebola outbreak in the Democratic Republic of the Congo continues to rage on, with no end in sight. In this exclusive MedPage Today video, two infectious disease experts — Peter Hotez, MD, of Baylor College of Medicine in Houston and Aneesh Mehta, MD, of Emory University School of Medicine in Atlanta — discuss current efforts to contain the outbreak through vaccination, as well as hope for new therapeutics currently being studied more carefully in clinical trials. Hotez and Mehta also address the problem of civil unrest disrupting disease prevention and treatment.
Following is a transcript of their remarks:
Hotez: I think it’s important to go back to the year 2014 when we had a horrific Ebola outbreak in West Africa, Guinea, Liberia, Sierra Leone, and we really needed to understand what would be the impact of this VSV Ebola vaccine called the recombinant VSV-ZEBOV vaccine in an outbreak setting. So far, the indications are that this is a very effective and relatively safe vaccine. As a consequence of that, when the current outbreak happened in North Kivu in Democratic Republic of Congo, there was a lot of interest to see whether or not this vaccine could control that outbreak, and my understanding is as of this point, more than 30,000 people have received the Ebola vaccine. My sense is that it’s having a big impact because although we’ve had more than 400 Ebola cases and 200 deaths, I think those numbers could have been far worse had those 30,000 individuals not been vaccinated.
Mehta: There are no approved therapies specific for Ebola viral disease. There are several potential products out there, medical countermeasures, as we call them. The one with the most experience is a product called Zmapp, which is a monoclonal antibody preparation that has three antibodies directed against Ebola. And that was used during the 2014 to 2016 outbreaks, sort of as a compassionate use. However, towards the end of the outbreak, there was a study called the PREVAIL II study that was performed in Liberia where they were able to actually enroll several patients with Ebola. Unfortunately they didn’t meet their enrollment targets, and so it’s statistically, we’re not sure if the Zmapp product actually provided a significant benefit to patients with Ebola, but it definitely looked towards that direction. And so that has been sort of the focus of preparation for Ebola therapy.
Hotez: For this group of what we call the “neglected tropical diseases” or NTDs, like Ebola, but also what we’re working on, like schistosomiasis, leishmaniasis, and chagas disease. Unfortunately, the world has responded by saying you only get one shot on goal, you only get one choice of modality. And I don’t know where that comes from, but we’ve got to break that idea because the other neglected tropical diseases are every bit as complex as AIDS, malaria, and tuberculosis. We need multiple modalities.
Mehta: In Africa, currently there’s an outbreak in Democratic Republic of the Congo and there, through a multinational consortium, there is a large clinical trial that has opened, and this clinical trial does include the Zmapp product as one arm, but they are also evaluating two other good potential products. One being Remdesivir which is a direct acting antiviral agent that has broad activity but does have activity against Ebola viruses. And then, the third product that they’ll be evaluating is a product known as MAB114, and this is a monoclonal antibody that actually was derived from a survivor of a previous outbreak in that same area in the Kikwit outbreak. And that was discovered and cloned by researchers at the National Institutes of Health, NIH here in the United States, and then made into a product and is now ready for clinical trials.
Now with these clinical studies that are well developed, we will really be able to get some really nice data that will help inform clinicians and developers of new medical countermeasures, specifically both the extended access protocol here in the United States and the multi-national clinical trial, we’ll look at overall mortality with Ebola comparing the products that are being used to standard of care in historical controls. In addition, we will be collecting samples from patients during the course of therapy and afterwards to one, understand how these products are working within the body, what the levels they are able to achieve, and if they’re working directly against the viruses themselves.
Hotez: So the problem that we’re facing is not really a technological problem, it’s a social problem, it’s a problem of political instability and conflict which blocks access for the vaccinators to go into affected areas and do their job. And this has actually become a new important 21st century theme with regard to neglected tropical diseases. So, an important lesson learned here is that whenever we see a serious level of conflict and political instability, we have to recognize that a catastrophic epidemics of neglected tropical diseases will surely follow. So this has become a recurring theme, and I think the international community has not really figured this one out yet. How to preemptively mobilize healthcare workers and lifesaving neglected tropical disease technologies when conflict arises.