Wanted: Ebola Vaccine

Army’s Medical Research Institute of Infectious Diseases pitches in to stem the tide.

By Cheryl Pellerin, DoD News

During a recent interview, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) scientists described their vaccine and drug-development research, development processes, and products in development for the Ebola virus and other infectious diseases.

“Dozens of vaccine candidates are being created worldwide, especially with this outbreak, and all of them have to go through an FDA (Food and Drug Administration) regulatory pathway,” said Dr. John M. Dye Jr., chief in USAMRIID’s Viral Immunology Branch. “The vaccines we’ve been working with here all express one particular protein of the virus, and many of these vaccines have been shown to be 100 percent [effective] in nonhuman primates, or monkey studies.”

Clinical Studies

USAMRIID has worked with the two Ebola vaccines now in clinical trials at the National Institutes of Health and the Walter Reed Army Institute of Research, and many others over the years. Most of the vaccine candidates target Ebola Zaire, one of five species of Ebola virus, and the one that’s now causing the West Africa outbreaks.

In their medical countermeasures work, USAMRIID scientists already had created a trivalent vaccine—one that contains three components. They are Ebola Zaire, Sudan virus, and Marburg virus—another highly lethal virus that’s in the same filovirus group as Ebola.

The trivalent vaccine is still going forward, Dye said, but a vaccine for Ebola Zaire was spun off in a separate program, “where they’re taking just the Zaire forward and then we’re continuing work on the trivalent cocktail—Zaire, Sudan, and Marburg—with the idea that eventually we’re going to have to cover all those bases.”

One vaccine candidate in clinical trials is based on recombinant, or genetically engineered, virus from an animal disease called vesicular stomatitis. An Ebola virus protein is modified into a vesicular stomatitis virus, and that virus acts as a vector, or carrier, to deliver the Ebola protein into the human body. The vaccine is called VSV-EBOV.

Human Testing

Human testing to evaluate safety of VSV-EBOV is underway at the National Institutes of Health Clinical Center in Bethesda, MD. Researchers at the National Institute of Allergy and Infectious Diseases, or NIAID, are conducting an early phase trial to evaluate the VSV-ZEBOV candidate for safety and its ability to generate an immune system response in healthy adults who receive two intramuscular doses.

At the same time, the Walter Reed Army Institute of Research is testing the vaccine candidate as a single dose at its Clinical Trials Center in Silver Spring, MD, NIH officials said.

The other vaccine in clinical trials is a recombinant chimpanzee adenovirus, or cold virus. An Ebola virus protein is engineered into a chimpanzee adenovirus to deliver the vaccine, called ChAd-EBOV, into people.

In early stage clinical trials, again designed to assess vaccine safety and immune response, the National Institute of Allergy and Infectious Diseases, part of NIH, will test two versions of the NIAID/GlaxoSmithKline vaccine. One is a bivalent, or two-component, version containing genetic material from Ebola Zaire and Ebola Sudan. The other is a monovalent, or single-component, version that contains only genetic material from Ebola Zaire.

Lead art: After Ebola is confirmed, doctors and scientists converge within days. (Pascale Zinten, MSF / AFP / Getty Images / Newscom)