Bird Flu Vaccine: 'A Long Way to Go'
In Race to Make Bird Flu Vaccine, Finish Line Still Out of Sight
Stretching the Bird Flu Vaccine Stockpile continued...
"Earlier studies suggested immunity would take a larger dose of H5N1 vaccine than regular flu shots," Treanor said. "So I don't think anyone was shocked. ... We certainly had hoped it would be better but we are not surprised."
In fact, the vaccine may very well work better than it appears. Treanor and colleagues were looking for antibody levels that seemed to protect people during a 1997 outbreak of H5N1 bird flu virus in Hong Kong. While high-dose bird flu vaccine stimulated this kind of antibody response in only half of study recipients, Treanor says lower antibody levels may very well be protective.
If that's the case, the vaccine may actually be better than it now looks. But there's no way to tell. Bird flu is not spreading among humans. And researchers, of course, aren't exposing any study volunteers to potentially lethal bird flu virus.
New Vaccine Techniques
Regardless of how well this vaccine works, all kinds of new bird flu vaccines are in the works. In one major step forward, the U.S. government is helping vaccine manufacturers move from the tried-and-true method of growing vaccine virus in chicken eggs to much faster cell-culture techniques.
Speed may in fact be the name of the game. That's why this study is so important. Bird flu vaccines now under development will pave the way for rapid licensing of newer vaccines. And new vaccines will be needed fast if the bird flu virus mutates to a form that causes a human pandemic.
"This virus, if it evolves to the point of being able to spread from human to human, would be different than the Vietnam 2004 strain tested and reported here," Fauci said. "But we hope that simultaneously with testing these vaccines, and getting good feel for the scope and tolerability of this vaccine, we would do two things. We will stockpile a modest amount, so even if there is not a perfect match, there would be some benefit. At the same time, we would isolate the putative virus that would go from person to person and develop a vaccine for that."