Live-Attenuated Zika Vaccine Candidate Successful in Mice

A developmental live-attenuated Zika vaccine showed complete protection from the virus in mice after a single vaccination dose, according to new research published in Nature Medicine.¹

The research was led by teams from the University of Texas Medical Branch (UTMB) at Galveston and Instituto Evandro Chagas at the Ministry of Health in Brazil.

Researchers created the vaccine by engineering the Zika virus by deleting 1 segment of the viral genome — an approach that has been successful in the development of a dengue virus vaccine. A single immunization dose was shown to produce strong immune responses and prevented the virus from infecting the mice. Additionally, the results found that the vaccine demonstrated a promising safety profile when compared with clinically approved live-attenuated vaccines.

“A successful vaccine requires a fine balance between efficacy and safety,” Pei-Yong Shi, senior author and I.H. Kempner professor at UTMB, said in a press release about the study.² “Vaccines made from attenuated live viruses generally offer fast and durable immunity, but sometimes with the trade-off of reduced safety, whereas reduced inactivated and subunit viruses often provide enhanced safety but may require several doses initially and periodic boosters.”

Shi noted that the development of a live-attenuated vaccine that demonstrates a balance of both safety and efficacy will be vital in the prevention of Zika virus, especially in developing countries.

The researchers concluded that the safety and efficacy results indicate that further development of the investigational live-attenuated Zika vaccine candidate is warranted.

Reference

• Shan C, Muruato AE, Nunes BTD, et al. A live-attenuated Zika virus vaccine candidate induces sterilizing immunity in mouse models. Nature Med. 2017. doi:10.1038/nm.4322.
• The first live-attenuated vaccine candidate completely protects against Zika infection [news release]. Texas. UTMB’s website. https://www.utmb.edu/newsroom/article11496.aspx. Accessed April 10, 2017.