An experimental Zika vaccine developed by US scientists has been found in two early clinical trails to be safe and promising in preventing infection by the deadly virus.
The findings, published in the journal Lancet, showed that it induced an immune response in healthy adults.
The investigational vaccine, developed by scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health, includes a small, circular piece of DNA called a plasmid.
Scientists inserted genes into the plasmid that encode two proteins found on the surface of the Zika virus.
The researchers found that when the vaccine was injected into muscle, the body produced proteins that assemble into particles that mimic the Zika virus and trigger the body to mount an immune response.
For clinical testing, the researchers developed two different plasmids – VRC5288 and VRC5283. They were tested in two separate trials.
The scientists analysed blood samples obtained from participants four weeks after their final vaccinations.
They found that 60 to 89 per cent of participants generated a neutralising antibody response to VRC5288, whereas 77 to 100 per cent of participants generated a neutralising antibody response to VRC5283.
“Following early reports that Zika infection during pregnancy can lead to birth defects, NIAID scientists rapidly created one of the first investigational Zika vaccines using a DNA-based platform and began initial studies in healthy adults less than one year later,” said NIAID Director Anthony Fauci.
“NIAID has begun Phase 2 testing of this candidate to determine if it can prevent Zika virus infection, and the promising Phase 1 data published today support its continued development,” Fauci said on Monday.