UC Davis shelves WNV vaccine for now

The University of California, Davis, (UC Davis) Center for Equine Health has shelved blueprints for a new West Nile Virus (WNV) vaccine.

The university concedes that Fort Dodge Animal Health owns the marketfor the equine WNV vaccine and has no plans to steal anyone's thunder yet,according to one school official.

But its work continues.

Dr. Greg Ferraro of UC Davis, who is helping raise funds for the school'svaccine development, says researchers at UC Davis have developed a constructfor a recombinant-type vaccine.

The recombinant vaccine is a new generation of vaccines where a pieceof DNA or RNA is removed from the virus and used to create protection.

The vaccine in the works has already been used for equine infectiousanemia with proven effectiveness. Researchers are confident it can be modifiedfor West Nile Virus.

Old kid on block

Ferraro says the university has been conducting research on the recombinantvaccine since WNV's first appearance in Queens in 1999. Of late, the universityfinished a study that was conducted on horses in South Africa where WNVis endemic.

Although South Africa's WNV strain is slightly different, "possiblywe could take the part of the virus DNA that causes horses to get immunityfrom the nonpathogenic strain and protect against the pathogenic strain,"he explains. "The advantage is that 1) it's much more specific in gettingyour immunogenic response and 2) you don't have to worry about properlykilled virus vaccine or modified live virus in any kind of viral drift.

"If you're working with DNA of the viruses you should be able tocreate a specific immunity that is more reliable."

Yet the work remains on hold for one, to allow Fort Dodge the chanceto prove efficacy, and secondly, for economic reasons.

"The problem with it is recombinant vaccines are more sophisticatedvaccines and much more expensive to produce than traditional killed or modifiedlive virus vaccines," says Ferraro.

"When you have a conditionally licensed killed vaccine out there,if that is effective we probably wouldn't go forward with designing or developingthis other vaccine, because it would cost more money."

In light of a recent Fort Dodge abstract paper citing preliminary efficacyresults, Ferraro says the university's decision is to "wait and see"if there is still a need for the vaccine. A decision will not likely bemade until next year.

The Maurice Stans Foundation is the primary financer of the UC Davisproject.

Looming threat

While the country reacts to the devastation of WNV, Ferraro says he keepsone eye on the horizon.

Through cooperative work with the University of Pretoria in South Africa,he says researchers are also studying African horse sickness, a pathogenicdisease.

"That's the one we really need to worry about - that's a much moreserious disease. West Nile is serious and we're taking it seriously andworking on it, but really we're looking at it as a preparatory thing formore serious diseases down the road."