This is a multicenter,randomized study to evaluate safety, immunogenicity, and efficacy of a 3-dose vaccination regimen with the Zika virus wildtype (ZIKVwt) DNA vaccine, VRC-ZKADNA090-00-VP or placebo (VRC-PBSPLA043-00-VP). The placebo is a sterile phosphate-buffered saline (PBS). The hypotheses are that the ZIKVwt DNA vaccine will be safe and will elicit a ZIKV-specific immune response.