Zika Vaccine Candidate on Track for Field Testing

October 5, 2016
Jennifer Barrett, Assistant Editor

The top vaccine candidate for Zika virus is expected to be ready for field testing next year in the event of outbreaks in the United States.

The top vaccine candidate for Zika virus is expected to be ready for field testing next year in the event of outbreaks in the United States.

The US National Institute for Allergy and Infectious Disease (NIAID) Vaccine Research Center has developed a DNA vaccine to protect against Zika that shows promising results so far. The vaccine contains a fragment of Zika’s genetic makeup recreated synthetically in the laboratory, and it’s intended to produce small virus-like particles similar to Zika to prompt an immune response that would protect the body from future infection.

Researchers reported that the DNA vaccine was successful in protecting 17 of 18 monkeys from the Zika infection in a study published last month in Science. According to US health officials, the vaccine is now ready to be tested in human-based field trials.

“This trial is right on target—in fact, a bit ahead of time,” stated NIAID Director Anthony Fauci, MD. “It is projected we will have enough information to determine safety and whether it induces the kind of response we predict would be protective.”

Researchers have recruited 80 volunteers for phase 1 trials, and the vaccine is on track to begin phase 2 field testing by January 2017. The phase 1 trial will test the vaccine in a small group of subjects, while the phase 2 trial will test the effectiveness of the vaccine in larger numbers of individuals. Phase 2 trials will likely include between 2400 and 5000 individuals from at least 15 locations where active Zika transmission is occurring, potentially including the United States.

Concerns over Zika virus outbreaks in the United States grew when researchers detected more mosquito species carrying the virus. The CDC reports that 21 infants have been born in the United States with birth defects that have evidence of possible Zika virus infection as of September 22, 2016. Earlier this year, the CDC issued advisories to pregnant women against travel to areas with Zika outbreaks.

New funding authorized by Congress, which earmarked $1.1 billion to fight Zika, is key to helping propel efforts to combat the virus. For example, the NIAID will be able to provide enough doses in advance of the next Zika outbreak.

The DNA-based shot is the furthest along of 9 candidate Zika vaccines so far, and it will be ready for field testing in the event of Zika outbreaks in 2017. In the meantime, Zika education can help early identification of symptoms and prevent further transmission of the virus.