Zika Program Overview
VBI is applying its eVLP Platform in the development of a preventative Zika virus (“Zika”) vaccine candidate. Enveloped virus-like particle (“eVLP”) vaccines closely mimic the structure of viruses found in nature, but without the viral genome, potentially yielding safer and more potent vaccine candidates.
VBI is developing a bivalent Zika vaccine candidate consisting of E glycoprotein (found on the surface of Zika virus) and NS1 glycoprotein (secreted during Zika viral replication). Preclinical testing suggests that Zika eVLPs may present Zika target proteins in an optimal shape and conformation, potentially allowing for a potent immune response. VBI plans to conduct additional testing in animal models to validate its approach.
Aedes Species Mosquito
Zika Medical Need
Zika is a mosquito-borne virus, from the genus Flavivirus. Zika is spread primarily through the bite of an infected Aedes species mosquito, but some evidence suggests that it may also be transmitted sexually or during childbirth.1
The first formal description of Zika virus was published in 19522 but interest in the virus was limited for many years. It was not until 2007 that the first Zika outbreak in humans was recorded.3 Over the past decade, Zika has begun to spread outside of tropical regions of Africa and Asia with serious resulting complications.4 Between January 2014 and February 2016, 33 countries reported circulation of the Zika virus. In February 2016, the World Health Organization (“WHO”) declared Zika a Public Health Emergency of International Concern (“PHEIC”), saying that the virus was “spreading explosively” in the Americas.
While the acute manifestations of Zika infection are typically mild, the disease has been associated with a number of neurological complications.5 There is scientific consensus that Zika can cause congenital microcephaly, a condition where a child is born with a smaller than expected head due to abnormal brain development. Zika may also cause Guillain-Barrė syndrome (“GBS”), a disorder in which the body’s immune system attacks the nerves, leading to muscle weakness or, in severe cases, paralysis. There is currently no vaccine to prevent Zika infection.
- Zika information from the Centers for Disease Control and Prevention. Visit resource >>
- Areas with Zika in the U.S. with data from ArboNET. Visit resource >>
- Background on Zika and complications from the World Health Organization. Visit resource >>
- World Health Organization Strategic Response Plan for Zika. Visit resource >>
VBI is developing a bivalent Zika vaccine candidate consisting of a surface E glycoprotein and an internal NS1 glycoprotein. E glycoproteins are found on the surface of the Zika virus. NS1 glycoproteins are secreted during Zika viral replication and may generate a cytotoxic T cell response important for cellular immunity.
During recent testing, VBI used a cell entry assay to confirm the presence of E glycoproteins on the surface of its Zika eVLPs; the conformation was found to be suitable for receptor binding and cell entry. VBI is planning to conduct testing in animal models to help validate the immunogenicity and protective potential of its approach.
- Dick GW, Kitchen SF, Haddow AJ. Zika virus. I. Isolations and serological specificity. Trans R Soc Trop Med Hyg. 1952;46(5):509-20.
- Duffy MR, Chen TH, Hancock WT, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. N Engl J Med. 2009;360(24):2536-43.