October 2, 2014

Ebola Virus Disease Update: Lags in Drug and Vaccine Development Accelerate Crisis

The urgency of calls for reliable and scaled public health responses to the magnitude of the international Ebola virus disease (EVD) outbreak is increasing; a media frenzy over the apparent emergence of Ebola in Dallas, TX is underway. At the present time, over 7,000 cases and over 3,300 deaths are attributed to the outbreak concentrated in West Africa, where the virus emerged earlier this year. The crisis requires a combination of public health resources (personnel, facilities, diagnostic capabilities) and effective countermeasures (vaccines, drugs). To date, the most effective drug against the  virus appears to be ZMapp, an antibody-based treatment developed by Mapp Biotherapeutical. However, ZMapp supplies are limited, and efforts to scale up production, while necessary, will still not produce enough to meet demand. An expert consultation called by the World Health Organization this week to review vaccine candidates has identified two Ebola vaccines that are ready for Phase I clinical trials. Scheduled milestones for the testing and evaluation of these potential vaccines are now published. Even in a best case scenario, in which a vaccine candidate performs well enough to justify scaleup and distribution, WHO does not anticipate that a significant number of vaccines to be ready before around March, 2015. The WHO meeting participants noted the unprecedented severity and spread of this viral disease relative to other public health crises: 
Participants also drew heavily on lessons learned, in the African setting, during trials for candidate malaria, HIV/AIDS, cholera, epidemic meningitis, hepatitis B, and other vaccines. As some experts noted, never again can the international community allow what boils down to “market failure” to create such catastrophic suffering for humanity in any country, in any region of the world. The sense of urgency and need for speed, without compromising the integrity of studies or the quality of their data, are fully justified by the dire situation in affected countries and the risk that other countries may soon experience their first imported cases. The Ebola outbreak currently ravaging parts of West Africa is the most severe acute public health emergency in modern times. Never before in recent history has a biosafety level 4 pathogen infected so many people so quickly, over such a wide geographical area, for so long.
The CDC has already estimated that 1.4 million cases of EVD could emerge by January next year. Case projections from WHO are smaller, but both agencies point out that a near-term ability to reverse the course of EVD will depend on successful public health efforts, including patient isolation and contact avoidance measures. Drugs and vaccines will not be produced fast enough in the short term to meet demand, but the efforts described above are good starts. More generally, as the WHO acknowledged with its reference to “market failure,” it is clear that government expenditures for research on countermeasures need to continue, but the development of a true pipeline from lab to clinic is still lacking. That is a translational failure here: the emergence of rare but deadly outbreaks of diseases like Ebola are not met with stockpiles of drugs. The U.S. Strategic National Stockpile maintains supplies of drugs for use in viral epidemics, but these are directed to the more familiar diseases such as influenza and anthrax. The current Ebola outbreak illustrates the consequences of focusing national resources too narrowly on the usual suspects in bioterrorism or pandemic crises, with the consequence that new or remote pathogens emerging in the U.S. are not met immediately with effective countermeasures that would contain disease outbreaks.

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