Thursday, October 05, 2006

A New West Nile Vaccine




Intervet has just released a new vaccine for West Nile Virus called "Prevenile". This is unique in that it uses a chimera technology . A recent article is available in "the Horse".

(PreveNile is based on ChimeriVax technology from Acambis, a leading biotechnology company specializing in the discovery, development and manufacturing of human vaccines to prevent and treat infectious diseases such as WNV, dengue, Japanese encephalitis, and smallpox.

"This is the same technology being tested for the first-ever human WNV vaccine, which is currently in Phase II research trials," says Jahde. "The ChimeriVax technology combines two similar flaviviruses (yellow fever--YF, and WNV) into one, creating a chimera vaccine."

PreveNile is a WN-YF chimera vaccine created by replacing the structural genes of the attenuated human yellow fever (YF-17D) vaccine with the structural genes of WNV.

The YF-17D human vaccine is a safe, highly effective, well-tolerated, attenuated vaccine that has been used for more than 60 years in more than 400 million people.)

Dr Maureen Long at the Univ. of Florida did alot of work on this project and found it far better at providing protective immunity. She did a study where she innoculated infective virus directly into the spinal fluid of horses that were vaccinated with the Chimera vaccine and found it to provide 100% survivability.

"PreveNile is proven 95% effective and shown to significantly reduce clinical signs of WNV in horses vaccinated with a single dose as compared to unvaccinated horses," says Long. "Vaccination resulted in 100% survivorship and resulted in a statistically significant reduction in clinical signs of WNV disease. In addition, the vaccine was shown to provide full 12 month protective immunity against WNV disease in unvaccinated yearlings.

"This type of protection is particularly important for na├║ve and previously unvaccinated horses, providing added assurance in the face of an outbreak," Long adds.

We usually let things settle out and start using new vaccines after about 6 months of being on the market, however the research is so compelling that we are switching over this month and will start vaccinating with it right away.