February 7, 2008

Pittsburgh scientists create new H5N1 vaccine

Researchers at the University of Pittsburgh's Centre for Vaccine Research have produced a vaccine against the H5N1 virus which has shown promising results. 

The study, which is already published by the Public Library of Science, reveals that the vaccine has produced a strong immune response in mice and protected them from death following infection with the H5N1 virus. The vaccine -- engineered by Novavax, Inc -- is being tested in humans in an early-phase clinical trial.

The vaccine uses virus-like particles (VLPs) that are recognised by the immune system as a real virus but lacks genetic information to reproduce, making it a potentially safer alternative for a human vaccine. Given the mutating nature of H5N1, the vaccine was engineered to encode genes for three influenza viral proteins to offer enhanced protection against possible new strains of the virus.

During the test, mice immunised 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 were 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.

According to Ted Ross, Ph.D, lead author of the study and an assistant professor at the university's research centre, VLPs may be advantageous over other vaccine strategies because they are easy to develop, produce and manufacture. Using recombinant technologies, Ross said a vaccine effective against the current circulating strain of virus could be manufactured within 12 weeks, making it a cost-effective counter-measure to the threat of an avian influenza pandemic.