An experimental gene-based Zika vaccine looks promising in phase 1 trials, the US National Institutes of Health reports in a press release.
The vaccine, developed by researchers at the National Institute of Allergy and Infectious Diseases, is made up of a plasmid that contains two genes that encode proteins found on the surface of the Zika virus. The researchers made two versions of the plasmid, one dubbed VRC5288 and the other called VRC5283, that varied slightly in the regions they target.
In a randomized phase 1 trial of healthy volunteers, the researchers found that both vaccines were safe and well tolerated, as they report in the Lancet this week. Additionally, they reported that, in blood samples obtained from participants four weeks after vaccination, between 60 percent and 89 percent of participants had neutralizing antibody response to VRC5288, while between 77 percent and 100 percent did to VRC5283. All of the 14 people who received split-dose vaccinations of by needle-free injection had an antibody response, they add. Based on this, the NIAID researchers say VRC5283 seems more promising.
In its release, NIH adds an international efficacy trial began last March and that it aims to enroll 2,490 healthy participants from areas of Zika transmission in it.