First live, attenuated vaccine completely protects mice subjects against Zika virus infection

According to a recent study conducted by the University of Texas Medical Branch (UTMB) at Galveston and the Instituto Evandro Chagas at the Ministry of Health in Brazil, the first live, attenuated Zika virus vaccine protected mice subjects against infection after just a single dose.

“We chose to pursue a vaccine made from live virus that has been sufficiently attenuated, or weakened, to be safe, and is able to illicit robust immune response to protect us from Zika virus infection,” Pei-Yong Shi, senior author of the study and UTMB professor, said. “Such live, attenuated vaccine has the advantage of single-dose immunization, rapid and strong immune response and potentially long-lived protection.”

UTMB said the vaccine was developed by deleting one segment of Zika’s viral genome and that a similar approach was used to develop a vaccine for dengue fever, both of which are part of the flavivirus family of viruses. Shi said that the vaccine maintained a good balance between safety and efficacy, producing a strong immune response.

“Our Zika vaccine showed promising safety profile in mice when compared with clinically approved live-attenuated vaccines, such as the yellow fever vaccine,” Shi said.

While the vaccine protected mice subjects from infection, it is still in the development stage and has not yet been tested in a clinical human trial.

Zika virus is typically transmitted by the Aedes aegpyti species mosquito and sexual contact. Symptoms in most cases involve joint pain, fever, rash, and headaches. More severely, the virus has been linked to microcephaly of the fetus in pregnant women and Guillain-Barré syndrome.

Support for the study was provided by the University of Texas System, the U.S. Centers for Disease Control and Prevention, the National Institutes of Health, and the Pan American Health Organization.