March 6, 2002

1 min read

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Hybrid Vaccine Protects Mice from West Nile Virus

By Kate Wong

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Researchers have developed a vaccine that protects mice against West Nile virus (WNV), according to a report published in the current edition of the Proceedings of the National Academy of Sciences. Tests of the vaccine in monkeys are slated to begin next month, and human trials could start before the year is out.

The mosquito-borne WNV, which in humans can cause potentially deadly encephalitis, first appeared in North America in 1999. Since then it has claimed the lives of seven people and made 80 others seriously ill. To develop the vaccine, Alexander Pletnev of the National Institute of Allergy and Infectious Diseases and his colleagues enlisted the help of WNV's close cousin, dengue virus, which does not attack the central nervous system. By substituting certain WNV genes with the dengue variety, the team created a hybrid virus that stimulates a strong immune response without infecting the brain. None of the mice that received the hybrid vaccine developed WNV when later exposed to it.

Because one of the dengue viruses used in the construction of the hybrid virus has already been shown to be safe in humans, the researchers hope that their vaccine will advance swiftly to human clinical trials. "We must remain vigilant and act quickly if we are to keep ahead of emerging and re-emerging infectious agents such as West Nile virus," says NIAID director Anthony Fauci. "Disease-causing microbes will continue to adapt and continue to thrive, so we cannot let down our guard."

Kate Wong is an award-winning science writer and senior editor for features at Scientific American, where she has focused on evolution, ecology, anthropology, archaeology, paleontology and animal behavior. She is fascinated by human origins, which she has covered for nearly 30 years. Recently she has become obsessed with birds. Her reporting has taken her to caves in France and Croatia that Neandertals once called home to the shores of Kenya’s Lake Turkana in search of the oldest stone tools in the world, as well as to Madagascar on an expedition to unearth ancient mammals and dinosaurs, the icy waters of Antarctica, where humpback whales feast on krill, and a “Big Day” race around the state of Connecticut to find as many bird species as possible in 24 hours. Wong is co-author, with Donald Johanson, of Lucy’s Legacy: The Quest for Human Origins. She holds a bachelor of science degree in biological anthropology and zoology from the University of Michigan. Follow her on Bluesky @katewong.bsky.social

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