Rapid development of a DNA vaccine for Zika virus
A DNA vaccine candidate for Zika The ongoing Zika epidemic in the Americas and the Caribbean urgently needs a protective vaccine. Two DNA vaccines composed of the genes that encode the structural premembrane and envelope proteins of Zika virus have been tested in monkeys. Dowd et al. show that two doses of vaccine given intramuscularly completely protected 17 of 18 animals against Zika virus challenge. A single low dose of vaccine was not protective but did reduce viral loads. Protection correlated with serum antibody neutralizing activity. Phase I clinical trials testing these vaccines are already ongoing. Science, this issue p. 237 DNA vaccine induced neutralizing antibodies largely protect monkeys after experimental challenge by virus infection. Zika virus (ZIKV) was identified as a cause of congenital disease during the explosive outbreak in the Americas and Caribbean that began in 2015. Because of the ongoing fetal risk from endemic disease and travel related exposures, a vaccine to prevent viremia in women of childbearing age and their partners is imperative. We found that vaccination with DNA expressing the premembrane and envelope proteins of ZIKV was immunogenic in mice and nonhuman primates, and protection against viremia after ZIKV challenge correlated with serum neutralizing activity. These data not only indicate that DNA vaccination could be a successful approach to protect against ZIKV infection, but also suggest a protective threshold of vaccine induced neutralizing activity that prevents viremia after acute infection.
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