Ebola is possibly one of the deadliest diseases we know today with a total death count upwards of 2 thousand since its identification in 1974, roughly 50 percent to 90 percent of those infected. In the current outbreak -- spread across Liberia, Sierra Leon, Guinea, and Nigeria -- it is confirmed responsible for some 834 deaths. Despite this staggering death rate, there is no cure for Ebola.
The lack of testing and approval is because of Ebola’s nature as a viral infection. With a high percentage of deaths and its progression, it isn't the sort of infection you can give people in order to test the efficacy and side effects of treatments or vaccines. Pharmaceutical companies and relief organizations alike have to merely wait for a new outbreak in order to even attempt treatment.
But that doesn't necessarily mean that treatments can't be used. Medical ethicists have agreed that patients who can give sound consent and understand the possible risks may take experimental, unapproved medication. Some health organizations do not agree, weighing the risks as potentially worse than the benefits.
Zmapp was developed by Mapp Pharmaceutical, and was tested on monkeys as a treatment against Ebola that has already displayed symptoms in a patient. The treatment was developed by infecting mice with fragments of the Ebola virus and utilizing the antibodies they produced in order to create the medication. Its method of action involves preventing the virus from being able to spread to new cells.
This particular drug has garnered attention because 3 Ebola patients have recovered quickly after treatment with it. The first of two patients administered this treatment experienced an all but miraculous improvement over night, while the second required 2 doses of Zmapp to show improvement.
Another treatment, this one developed by Tekmira Pharmaceuticals Corp., has also shown a lot of promise. This drug has actually been through a small Phase I clinical trial, with no adverse effects reported to date, and was funded by the US Department of Defense. It has been used largely as a post-exposure prophylaxis (i.e., a drug to be administered after infection but before signs and symptoms), but may be a valuable treatment to those more obviously infected. Its method of action involves RNA interference to fend off illness.
Inherently different from treatments (i.e., they're intended to prevent the disease), vaccines have had a slower track of development. A pharmaceutical company called NewLink is working with the US Department of Defense to develop a vaccine (VSV-EBOV) that will hopefully go into clinical trials soon. However, the Public Health Agency of Canada has sent its entire stockpile of roughly 1 thousand units to the World Health Organization. The US NIH's National Institute of Allergy and Infectious Diseases is also working on a vaccine, slated for clinical trials in the fall.
While not a vaccine, BioCryst is working with the US National Institutes of Health to develop a new antiviral to combat Ebola. It should be entering Phase I clinical trials before the end of the year.
These and other drugs are being used in the current Ebola outbreak and what we learn now will give us insight into the effectiveness of these drugs for the future.