Experimental Treatments for Ebola Virus


As per a panel of ethicists convened by the WHO, it is ethical to use therapy and vaccines that have been developed but never tested in humans given the size of the outbreak of Ebola.


What’s the difference between therapy and vaccine?

Vaccines are usually given to people before they are exposed to a virus or bacteria that cause a disease. A vaccine stimulates the immune system to generate antibodies and cellular immunity that can fight off an infection if it were to occur. Typically, therapeutics are provided to people who are already infected with the virus. With the experimental ZMapp treatment, the monoclonal antibodies bind to the virus, so that the human immune system can clear the virus.



What is ZMapp?

 ZMapp, being developed by San Diego-based Mapp Biopharmaceutical Inc., is an experimental treatment, for use with individuals infected with Ebola virus. The product is a combination of three different monoclonal antibodies that bind to the protein of the Ebola virus.

How effective is the experimental treatment?

Moreover, it is far from clear what effect, if any, ZMapp actually had on the two infected Americans, Kent Brantly and Nancy Writebol, who remain in isolation at Emory University Hospital in Atlanta. A 75 year-old Spanish priest who had been airlifted to Madrid from Liberia last week was also administered the same drug, a representative of his religious order told Europa Press Television. Members of the order were hopeful for his recovery, but the priest, Rev. Miguel Pajares, died.

 It is too early to know whether ZMapp is effective, since it is still in an experimental stage and has not yet been tested in humans for safety or effectiveness. Some patients infected with Ebola virus do get better spontaneously or with supportive care. It’s important to note that the standard treatment for Ebola remains supportive therapy.

This consists of the following measures:


balancing the patients’ fluids and electrolytes;

 maintaining their oxygen status and blood pressure; and

 treating them for any complicating infections.


How much supply is there?

The product is still in an experimental stage, and the manufacturer reports that there is a very limited supply, so it cannot be purchased and is not available for general use.


Is ZMapp a vaccine?

No. ZMapp is being developed as a therapeutic product for treatment of people infected with Ebola virus, but not to prevent infection in the same manner as a vaccine.


Are there other companies developing experimental treatments?

Two other companies, Tekmira and Biocryst Pharmaceuticals, receive funding from the Department of Defense’s Defense Threat Reduction Agency and have therapeutic candidates for Ebola in early development. The Department of Defense is working with a company called Newlink to develop an Ebola vaccine candidate. BioCryst , with NIH support, is working to develop an antiviral drug to treat Ebola virus that is expected to begin Phase 1 testing. Tekmira is developing an experimental treatment called TKM-Ebola, which is designed to harness a drug technology known as ribonucleic acid interference to combat the virus.


Matthias Schnell, director of the Jefferson Vaccine Center at Thomas Jefferson University in Philadelphia, explained that the vaccine he is developing with researchers from the U.S. National Institutes of Health is based on a human rabies vaccine.

Schnell's vaccine triggers the immune system to produce antibodies against three strains of Ebola. The vaccine contains the Zaire strain of Ebola that is currently spreading in West Africa, but it also includes the Sudan strain of Ebola and the Marburg virus, which is in the same family as Ebola and causes a similar disease.

So far, the vaccine has only been tested in monkeys, where it was found to protect against the Zaire Ebola virus.Before the vaccine could be available, it would have to be tested in humans to be sure it is safe and effective. That process would typically take as long as three years, Schnell said.

Dr. Ambreen Khalil, an infectious diseases specialist at Staten Island University Hospital in New York City, said, "This vaccine is promising, but won't help people already

infected." That is why Schnell is also involved in developing a treatment that would produce large amounts of Ebola antibodies that could be given to patients suffering from the disease. Schnell is working on producing human-like antibodies in cows. By vaccinating cows with the new vaccine, Schnell hopes to be able to produce large amounts of serum that will cure people with Ebola. Each cow could produce as many as 2,000 doses every two weeks.