A synthetic DNA-based vaccine against the Zika virus showed promising immune responses with no severe adverse reactions in humans, an interim analysis of a phase I trial found.
Following three doses of vaccine, 100% of patients produced binding antibodies, and 95% of patients produced binding antibodies following two doses of the vaccine, reported Pablo Tebas, MD, of the University of Pennsylvania in Philadelphia, and colleagues.
The most frequently reported adverse events were local to the injection site (pain, redness, swelling and itching), which was reported in half the participants, the authors said. Systemic adverse events were characterized as "uncommon" and included headache, myalgias, upper respiratory infection, fatigue, and nausea. With the exception of the injection-site reactions, the investigators concluded that just under 60% of adverse events were "unrelated to the vaccine administration."
And all this from just 1 to 2 milligrams - or 0.00035 to 0.00007 ounces of vaccine...