New Vaccine Against Deadliest Strain of Avian Flu Tested by Scientists

The new vaccine against the deadliest strain of avian flu has been engineered and tested by researchers at the University of Pittsburgh's Center for Vaccine Research and Novavax Inc. is published in the January 30 issue of the Public Library of Science. (PLoS ONE)

The New vaccine produced a strong immune response in mice and protected them from death following the infection of H5N1 virus. The vaccine is now being tested in humans in an early-phase clinical trial.

With recent outbreaks around the world of the avian flu it has prompted health officials to warn of its continued threat to global health and potential to trigger a flu pandemic. Lead author of the study, Ted M. Ross stated "While worldwide efforts of the avian flu control have been mostly successful, avian flu, like seasonal influenza, mutates year to year, creating new subtypes and strains that could easily and quickly spread among humans." "To stem the spread of a potential pandemic, we need stockpiles of vaccines available that can be readily adapted to enhance the immune system's response to new strains."

A future flu pandemic is inevitable because of the virus's ability to continually reinvent itself and the lack of broad immunity in humans, according to Dr. Ross. Influenza pandemics have occurred three times throughout modern history with deadly consequences. The first, the Spanish Flu of 1918, caused more deaths than World War I.

Unlike other avian flu vaccines, which are partially developed from live viruses, this vaccine uses a virus-like particle, or VLP, that is recognized by the immune system as a real virus but lacks genetic information to reproduce, making it a potentially safer alternative for a human vaccine, Ross explained.

To test the vaccine, researchers administered it to mice in one-dose and two-dose regimens. Mice immunized twice with the vaccine developed protective antibodies against H5N1 and were protected from disease and death when directly exposed to the virus. The researchers also compared modes of vaccine administration by delivering the vaccine to the muscle or the nose. Both methods of vaccine administration were equally effective. However, mice injected with the vaccine through the muscle developed more antibodies in the blood, while mice that received the nasal administration had more antibodies in their lungs.

"VLPs may be advantageous over other vaccine strategies because they are easy to develop, produce and manufacture," said Dr. Ross. "Using recombinant technologies, within ten weeks, we could generate a vaccine most effective towards the current circulating strain of virus, making it a cost-effective counter-measure to the threat of an avian influenza pandemic."