New vaccine may give long-term defense against deadly bird flu and its variant forms

A new vaccine that apparently can provide long-lasting protection for pathogenic bird flu, H5N1, and its mutations, has been developed by Purdue researchers in collaboration with the US Centers for... Click here for more information.

WEST LAFAYETTE, Ind. - A new vaccine under development may provide protection against highly pathogenic bird flu and its evolving forms, according to researchers at Purdue University and the Centers for Disease Control and Prevention who discovered the new preventative drug and have tested it in mice.

Unlike traditional influenza vaccines, the new vaccine could be produced quickly and stored for long periods in preparation for a pandemic of dangerous disease-causing avian influenza - H5N1 - and its variants, said Suresh Mittal, a Purdue virologist. In an earlier study with mice, he and his colleagues found that the vaccine protected against H5N1 for a year or longer. Because the studies have only been done in mice, it's not yet known whether the same results will be obtained in humans.

"We want to have a vaccine that can be stored in advance and have the potential to provide protection for a period of time until we can change the vaccine to match the latest form of avian influenza," Mittal said. "The combination of flu genes that we've used to produce the vaccine, I think, will provide that capability."

The importance of having a long-lasting, broadly protective vaccine is that it would give some cross-protection against new viruses with pandemic potential caused by mutations in currently circulating H5N1 viruses. This would give scientists time to develop a better vaccine that would match the latest form of the bird flu.

Mittal and his colleagues, including Suryaprakash Sambhara, the CDC principal investigator on the project, report their findings on the vaccine in the April 15 issue of The Journal of Infectious Diseases. In the December issue of Clinical Pharmacology and Therapeutics, Mittal, Sambhara and their collaborators published their findings of the long-lasting capabilities of the vaccine.

"In humans we want a vaccine to be fully effective for at least a year," said Mittal, a professor of comparative pathobiology. "How long it will last in humans, we don't know yet."

To produce the new vaccine, the scientists used a mutated common cold virus, known as an adenovirus, as a delivery system for important genes from two types of the H5N1 avian influenza. The adenovirus is incapable of multiplying and so cannot cause illness to people. By using the adenovirus vector technology, a couple of problems with existing vaccines used to fight annual flu outbreaks are solved.