According to Dr. Tom Monath, the scientific officer of the Acambis pharmaceutical company, human trials on a new vaccine for West Nile virus (WNV) can begin as soon as the FDA will give the green light (likely in October of 2003).
At the 2003 World Vaccine Conference in Montreal/Canada this summer Dr. Monath explained that Acambis has been doing research for a new vaccine against WNV since 1999 when this virus arrived in New York. The virus belongs into the same group of flaviviruses as dengue fever, yellow fever and Japanese encephalitis.
Yellow fever has been successfully prevented by vaccination with a live vaccine that has been modified considerably (called 17D attenuated vaccine). This strain is basically a harmless virus, which will induce a strong immune response in 100% of vaccinated people. If this is repeated every 10 years, a vaccinated person would be safe to travel in yellow fever infested areas. Based on this knowledge the researchers of Acambis have created a chimera virus where the yellow fever vaccine (attenuated virus 17D) is used as a vehicle in the center while the surface has been modified by incorporating parts of the WNV into its envelope. As this new vaccine virus has qualities of both the yellow fever vaccine virus and the WNV, it is called a chimera virus. The same technology has already been successfully applied to two other flavivirus vaccines, namely the dengue fever vaccine and the Japanese encephalitis vaccine.
The new WNV vaccine has been tested extensively in mice and monkeys and has been found sofar to be very safe and it is mounting a very good immune response. It is timely that human trials are being done now starting this fall as WNV seems to be expanding rapidly throughout the United States and Canada. The vaccine would be needed particularly for older people as in them the WNV disease presents much more violently with a higher death rate. However, visitors from Europe to the US and Canada will likely want to protect themselves as well before they travel.
Comment in July 2012: A vaccine for humans is still not available, for horses it is.
Last edited December 9, 2012