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By Dennis Thompson
HealthDay Reporter
THURSDAY, Sept. 22, 2016 (HealthDay News) -- An experimental DNA-based vaccine protected monkeys from infection with the birth defects-causing Zika virus, and it has proceeded to human safety trials, researchers report.
"The vaccine universally elicited antibodies from all primates, but for the animals that got a full dose of vaccine, 17 of 18 were protected from infection," said study co-author Ted Pierson. He is chief of the Viral Pathogenesis Section at the U.S. National Institute of Allergy and Infectious Diseases.
Based on these findings, researchers have begun clinical safety trials in healthy human beings, Pierson said. These trials will show whether the vaccine is safe in humans, and whether it prompts an immune system response as it did in monkeys.
"When a vaccine is effective in a lower primate species, it is a good signal that it will be effective in humans," said Dr. Amesh Adalja, a senior associate at the University of Pittsburgh's UPMC Center for Health Security in Baltimore. "The NIH vaccine candidates have cleared an important hurdle, and we are awaiting results from phase 1 human studies."
However, animal research does not always pan out in humans.
Zika is the first mosquito-borne virus known to cause terrible birth defects, most of them brain-related. The most common defect is microcephaly, in which a child is born with an abnormally small brain and skull. Thousands of babies have been born with Zika-linked microcephaly, most of them in Brazil, since an outbreak began in South America in April 2015.
Zika infections have been occurring in south Florida, with 43 cases as of Sept. 21, according to the federal Centers for Disease Control and Prevention. There have been no reports of microcephaly in the state.
Because of the ongoing transmissions, a Zika vaccine is important to prevent future birth defects, Adalja and Pierson said.
This potential vaccine contains a piece of DNA created synthetically in the laboratory from the Zika virus, Pierson said.
When introduced into the body, the DNA causes small virus-like particles to be secreted from cells, Pierson explained. These particles are not full-fledged Zika, but are similar enough to the virus that the immune system might produce an antibody response that will also protect against Zika.