New Bug-Virus Flu Vaccine Works
In Case of Flu Pandemic, Technology Promises Faster Vaccine
April 10, 2007 -- A flu vaccine made in insect cells works in humans, a small clinical study shows.
The new technology greatly speeds vaccine production and would save precious time if a flu pandemic breaks out.
University of Rochester flu researcher John Treanor, MD, is a researcher for the study in which 306 healthy adults got a single injection of the bug-cell flu vaccine.
"Even though the study was small, the results are very promising," Treanor said in a news release. "We've shown that the vaccine does work in the real world."
Treanor and colleagues at Cincinnati Children's Hospital and the University of Virginia report their findings in the April 11 issue of The Journal of the American Medical Association.
New Flu Vaccine Needs No Eggs
All of the currently approved flu vaccines are made in hens' eggs. That spells trouble for people with egg allergies. It spells even more trouble for vaccine makers.
Hundreds of millions of live, fertilized eggs are needed each year to make the world's flu vaccines. Each flu virus has to be specially adapted to grow in eggs. And technicians have to handle live viruses, creating safety issues.
These problems would be exponentially more troublesome if the current H5N1 bird flu virus becomes a human flu pandemic. As bad as this virus is for humans, it kills virtually 100% of infected chickens. That could doom a flu vaccine before it even gets off the ground.
Cell-based flu vaccine production systems use genetically engineered viruses to produce vaccine ingredients -- pieces of flu virus, not live virus itself.
The system tested by Treanor and colleagues uses an insect virus called a baculovirus to produce flu vaccine. The vaccine, FluBlOk from Protein Sciences Corp., can be made in one or two months less time than it takes to make an egg-based vaccine.
During the 2004-2005 flu season, Treanor and colleagues tested a FluBlOk vaccine containing the same vaccine ingredients as the current flu vaccine. Blood tests showed that the vaccine stimulated at least as much antiflu immunity as the currently approved vaccine usually does.
There were only two cases of flu among the vaccine recipients, while there were seven flu cases among the people who got mock vaccinations.
Interestingly, during the 2004-2005 flu season, the normal flu vaccine was not a good match for the flu "drift variant" type A H3N2 flu virus that circulated that year. However, the bug-cell-produced vaccine did seem to provide protection against the mismatch virus.
"Preliminary evidence of protection against a drifted influenza A(H3N2) virus was obtained, but the sample size was small," Treanor and colleagues note.