Precursor of vaccine now being tested in West Africa produced immune response in Ugandans
WebMD News from HealthDay
By Dennis Thompson
HealthDay Reporter
TUESDAY, Dec. 23, 2014 (HealthDay News) -- There's good news about the experimental Ebola vaccine that U.S. officials are preparing to test in West Africa -- new research shows a precursor of that vaccine produced a safe and potent immune response in Africans.
That earlier version of the vaccine, when given to more than 100 Ugandans in 2009 and 2010, prompted the production of antibodies and white blood cells that could potentially protect a person against infection by Ebola, said study author Dr. Julie Ledgerwood, chief of the clinical trials program in the U.S. National Institute of Allergy and Infectious Diseases' Vaccine Research Center.
"This is the first study to show comparable safety and immune response of an experimental Ebola vaccine in an African population," Ledgerwood said. "This is particularly encouraging because those at greatest risk of Ebola live primarily in Africa, and diminished vaccine protection in African populations has been seen for other diseases."
The U.S. National Institutes of Health (NIH) is about to start West African clinical trials for a new Ebola vaccine based on a chimpanzee cold virus, called chimp adenovirus type 3.
The vaccine uses the chimp virus to deliver pieces of Ebola genetic material to human cells, which hopefully will prompt an immune response that protects against infection.
The earlier vaccine used a less efficient DNA-based carrier to deliver the exact same Ebola genetic material that's contained in the new vaccine, Ledgerwood explained. She and her colleagues report results from the earlier trial in the Dec. 23 online issue of The Lancet.
"DNA gets into human cells pretty well, but chimp adenovirus gets into the human cell very well," she said. "It's a better delivery system."
Thus, the success of the earlier vaccine provides some hope that the new NIH vaccine will be safe for Africans and produce an immune response in them similar to that found in Americans during prior safety trials, Ledgerwood said.
The ongoing Ebola outbreak in West Africa has claimed 7,373 lives, according to the World Health Organization. The total number of cases in Guinea, Sierra Leone and Liberia now stands at 19,031.
source : Early Study Offers Hope for an Ebola Vaccine
