Background: West Nile virus (WNV) is a mosquito-borne flavivirus that can cause severe meningitis and encephalitis in infected individuals. We report the safety and immunogenicity of a WNV DNA vaccine in its first phase 1 human study.
Methods: A single-plasmid DNA vaccine encoding the premembrane and the envelope glycoproteins of the NY99 strain of WNV was evaluated in an open-label study in 15 healthy adults. Twelve subjects completed the 3-dose vaccination schedule, and all subjects completed 32 weeks of evaluation for safety and immunogenicity. The development of a vaccine-induced immune response was assessed by enzyme-linked immunosorbant assay, neutralization assays, intracelluar cytokine staining, and enzyme-linked immunospot assay.
Results: The vaccine was safe and well tolerated, with no significant adverse events. Vaccine-induced T cell and antibody responses were detected in the majority of subjects. Neutralizing antibody to WNV was detected in all subjects who completed the 3-dose vaccination schedule, at levels shown to be protective in studies of horses, an incidental natural host for WNV.
Conclusions: Further assessment of this DNA platform for human immunization against WNV is warranted.
Trial registration: ClinicalTrials.gov identifier: NCT00106769 .