Top 10 Innovations for 2009
#6 New Strategies for Creating Vaccines for Avian Flu
Flu pandemics pose an enormous threat to everyone. As the virus spreads and continues to reinvent itself-and with a lack of broad immunity in humans-pandemics are real concerns and inevitable. Most epidemiologists agree that the world is overdue for another lethal flu pandemic.
Recent outbreaks of avian influenza (bird flu), triggered by duck and chicken virus that can pass from the birds to humans, remains a continued threat. Experts believe that it is only a matter of time before this bird flu mutates and starts to spread from person-to-person around the globe with the help of international jet travelers. Without the protection from a special avian flu vaccine, it's estimated that even a mild strain of the virus could severely sicken a half million Americans and kill more than 200,000. By comparison, the typical flu we get each winter kills about 36,000 annually in this country.
Scientists are working to engineer effective vaccines against this killer bird virus, in particular against the most common and deadliest strain of avian flu, H5N1. Most vaccines employ a killed virus to stimulate the immune system. These vaccines have to be formulated to match the mutating flu strains and can take several months to manufacture using specially grown chicken eggs.
A newer vaccine approach that uses a mock version of the bird virus called a virus-like particle (VLP) may offer a better solution to protect people against infection from the deadly avian virus.
To create VLPs for avian flu, scientists build a structure similar to a virus except for the genetic material required for viral replication. Once injected into the body, VLPs attach to cells and trigger an immune response sufficient to protect a person if they become exposed to the virus. A recent human study reported that an experimental VLP vaccine produced a response against H5N1 in up to 94% of patients.
VLPs have several advantages over traditional flu vaccines: they are easier to develop, produce, and manufacture. Researchers only need to know the genetic sequence of the virus in order to create a vaccine against it; live virus is not needed to produce a VLP vaccine.
"Our niche is our ability to react quickly," says Penny M. Heaton, M.D., who has been involved in the testing of experimental VLPs against avian flu. "If the World Health Organization sees a new strain emerging in Asia and they know it can cause a pandemic, once they get us the genetic sequence of that strain, we can have the first vaccine produced in 10 to 12 weeks, which is half the time for egg-based vaccine production."