Originally created 03/05/02

Vaccine for Nile infection studied



Ray Davis knows what few people realize about mosquitoes in Augusta. The flying, biting pests are more than annoying - they can be debilitating and deadly. Mr. Davis found this out last year when he spent a month in a coma with the West Nile virus. He was one of six people in Georgia to get the virus, which left an Atlanta woman dead.

News that there is progress on a vaccine was welcome, Mr. Davis said.

"I don't want to go through that again," said Mr. Davis, 74, who is still trying to regain strength lost during his long hospital stay.

A report published today in the Proceedings of the National Academy of Sciences says a vaccine created by a team at the National Institute of Allergy and Infectious Diseases appears to work in mice.

The researchers took a weakened version of another mosquito-borne virus, called dengue virus, and replaced certain genes with those from West Nile. The vaccine produced a strong immune response in mice and will be tested soon on monkeys, and possibly humans, by the end of the year, the federal agency said.

Researchers chose dengue because it does not attack the central nervous system and would not cause the potentially fatal encephalitis that can accompany West Nile.

"I think the approach they are taking is very interesting," said Annie De Groot, the founder and chief executive officer of the biotech company EpiVax, which is working on a quicker test for West Nile.

Because West Nile and dengue are in a related family of viruses, there is also some "cross-reactivity" - immune cells that recognize dengue also recognize West Nile.

There is a strong genetic matchup between West Nile and Japanese encephalitis virus, for which there is already an approved vaccine, Dr. De Groot said.

"You could actually use JEV, the vaccine, against West Nile," Dr. De Groot said. Her lab is awaiting approval on a proposal to study that possibility.

"Since they have already been through the safety and toxicity studies, that's a faster route to actually getting a vaccine," Dr. De Groot said.

There are always concerns about using a weakened live virus vaccine because of potential side effects, said Keith Woeltje, hospital epidemiologist and infectious disease physician at the Medical College of Georgia.

"It's just making sure the side effects don't outweigh the benefits," Dr. Woeltje said.

Those infected with West Nile rarely get sick from it, and those who get sick rarely need hospitalization. The virus seems to cause the most damage among the elderly and the very young, and those people may be the best targets for vaccination, Dr. Woeltje said.

Need for the vaccine might depend in part on how many cases are diagnosed this year, and it is too early to tell how many that will be, said Jack H. Austin Jr., the infectious disease specialist at University Hospital who treated Mr. Davis.

"I predict we are going to see more cases," Dr. Austin said.

A vaccine would be a comfort, said Joyce Davis, Mr. Davis' wife.

"That would be great to have something to ward this off," she said.

Reach Tom Corwin at (706) 823-3213 or tomc@augustachronicle.com.