An investigational synthetic DNA vaccine (GLS-5700) seems to prompt an immune response against the Zika virus, but researchers caution that more data are needed on the vaccine’s long-term safety and efficacy, according to a phase 1, industry-supported trial in the New England Journal of Medicine.
Forty healthy adults received 1 or 2 mg of the vaccine at baseline, 4 weeks, and 12 weeks. Injections were followed by electroporation (use of a pulsed electric field to introduce the DNA into cells).
At 14 weeks, all patients had Zika-specific binding antibodies. Roughly 70% of the serum samples had 90% inhibition of Zika infection.
Next, mice were injected with the post-vaccination serum and then given a lethal dose of Zika; 92% survived. The authors write: “This finding suggests that the antibody response generated by the vaccine was protective in this infection model.”