GlaxoSmithKline develops comprehensive avian flu vaccine

To this point in the fight against avian flu, most proposed vaccines have focussed on particular strains of the infection, with each season bringing newer mutations that render last year’s successes inoperative. Yet as it is with regular flu, where the World Health Organization and other agencies collectively identify the seasonal flu strains to guide the creation of the consumer vaccine, those in the bird flu business hope for a similar catch-all. They received some assistance this month when phamaraceutical giant GlaxoSmithKline (GSK) announced that a new avian flu vaccine that had previously proved effective against a strain of H5N1 bird flu from Vietnam also protected them from a separate flu variant isolated in Indonesia. Exactly why, however, remains unsettled.

“When we’re vaccinating against pandemic flu, with no prior exposure, you would expect the response to be narrowly focused,” explained John Treanor of the University of Rochester. Yet, in blood tests, the GSK vaccine effectively neutralized both the Vietnamese and Indonesian strains. The question now is why. According to GSK, the reason may lie in the proprietary adjuvant system — those extra agents such as aluminum salts that play a critical role in forming the inactive elements of vaccines — but even that effect is not well understood, even by GSX, despite the fact that GSX researchers found that the immune response in human blood was 25 times stronger with the adjuvant present than without it. “Does it somehow cause a whole new spectrum of shapes on the surface proteins of the flu virus to be recognized? Or does it increase the amplitude of the immune response?” asked GSK’s Bruce Innis. “Those tests haven’t been done yet.”

Should GSX succeed in identifying the adjutants at work, public health officials believe it could be used to provide broader flu vaccine coverage without the need to reformulate for different years and regions. The work has also inspired the U.S. Department of Health and Human Services to buy $40 million worth of antigens to the Indonesian strain from GSX with an option to purchase the mysterious adjuvant system. “Since you don’t know which one, if any, of the bird flu strains might emerge as the pandemic strain, there is some advantage in an antibody that might be able to affect members of multiple strains,” said Treanor. “We know that the job of flu vaccine is to protect against not only what you put in the vaccine but also things that might occur in the future because [evolution] is ongoing.”

-read more in David Biello’s Scientific American report