West Nile virus (WNV), first identified in Africa in the 1930’s is transmitted to humans primarily through mosquito bites. Since its emergence in the United States in 1999, WNV has spread and established itself across North America. Statistics indicate that the severity of the virus has increased over time in the United States; of the 5,674 cases reported in 2012 to the U.S. Centers for Disease Control and Prevention, 51 percent were classified as neuroinvasive, and close to 300 people died from the virus. Texas reported the highest incidence of WNV in 2012, with 12,868 cases (33 percent of all U.S. cases).
Through the novel work of Dr. Kristy Murray, it has been shown that West Nile virus (WNV) can maintain a chronic infection in some humans and result in chronic renal disease. This finding is contradictory to what was originally thought, as it has been largely believed that like many other members of Flaviviridae, the virus is cleared by the immune system after an acute infection.
The National School of Tropical Medicine has now begun the development of a therapeutic WNV vaccine and is collaborating with Hawaii Biotech to use their WNV 80E antigen to develop a therapeutic WNV vaccine. As a vaccine against a chronic viral infection will need to induce an adaptive cellular response, as opposed to a humoral response, the current formulation of WNV 80E will need to be changed and optimized to accommodate this new vaccine. Additionally, immunogenicity and efficacy studies will be performed to test the different routes and doses of the vaccine as well as the optimal formulation.