West Nile Virus Vaccine Development

The vaccine is an important step in the prevention ofbased in Massachusetts, to begin the first human
West Nile Virus (WNV) Presently, there exists aclinical trials for a West Nile virus vaccine. The
vaccine for the West Nile virus in horses, but noAcambis vaccine contains genes from two different
vaccine has yet been developed for the West Nileviruses, yellow fever and West Nile.Acambis
virus in humans. The West Nile virus is a rapidlyVaccineResearchers at Acambis replaced some of
spreading health problem; hence, scientific efforts intothe yellow fever genes with genes of a surface
creating a vaccine for it have been accelerated inprotein for the West Nile virus. The Acambis vaccine
recent years.West Nile Virus Hot SpotsBoth Centralentered human clinical trials after performing well with
and South America are major hot spots for this virusmice, hamsters, monkeys and horses. In May 2005,
as they harbour significant numbers of the mosquitoAcambis, with its ChimeriVax technology, successfully
population. A complex network of interactioncompleted Phase I of their research, whereby 30
between the virus, the birds, and the mosquitoeshealthy adults received a high dose of
exists, and it is still somewhat poorly understood. InChimeriVax-West Nile vaccine, 15 received a low
order for the West Nile virus vaccine to be created,dose, and 30 control subjects received a placebo.The
it is imperative for scientists to fully disentangle andstudy indicated that 96% of the high-dose group and
comprehend the inter-connections. In 2006, there100% of the low-dose group developed West Nile
were 4,269 cases of West Nile virus reported, ofneutralizing antibodies 28 days after the initial
which 177 were recorded deaths in the U.S.Where toinoculation. In December 2005, Acambis announced its
BeginMany factors must be considered and manymove into Phase II, and September 2006 brought an
questions are still unanswered. Research on a vaccineannouncement outlining very promising results. The
against the West Nile virus must include thetrials involved testing the safety, tolerance and
following:    * Determination of how the virusimmunogenic qualities of the West Nile virus vaccine
replicates and spreads throughout the humanon healthy adults aged 18-40. The primary purpose of
body.    * Investigation into how the immunethis particular trial was the seroconversion rate or the
system reacts to the most serious form of the virus,percentage of candidates who developed neutralizing
West Nile encephalitis.    * Examination of theantibodies at a titre of at least 1:10.Results indicated
environment and the yearly maintenance of thethat over 97% of subjects seroconverted in 28 days
disease.    * Comprehension of how geneticafter one single dose of ChimeriVax-West Nile.
variation affects the virus and the disease.PresentOngoing trials are being performed on healthy, older
ResearchIn 2003, the West Nile virus had a greateradults who are most at risk of experiencing severe
impact on the population than in previous years. Thissymptoms resulting from a West Nile virus infection.
fact prompted Acambis, a biotechnology company