Vaccine from 2004 may fight current bird flu strain

Researchers have found that a stockpiled vaccine designed to fight the avian flu in 2004 can be combined with a vaccine that matches the current bird flu strain in order to protect against a potential pandemic.

According to the findings from the St. Louis University’s Center for Vaccine Development, public health officials can get ahead on fighting a pandemic caused by avian flu because they will not necessarily have to wait for a vaccine that matches the strain they are facing, reports.

Vaccinations can begin almost immediately by using a vaccine that is made from a related, yet mismatched, strain of flu that can prime the body for a matching second shot.

"A cornerstone of pandemic planning is the development of effective vaccines against avian influenza infection," Robert Belshe, director of the Center for Vaccine Development at Saint Louis University, said, according to "The results of the present study confirm the usefulness of vaccination with an H5 strain that isn't the current dominant strain."

Health officials are concerned that H5N1, or avian flu, could spread quickly and become a pandemic outbreak. H5N1 is a highly infectious and deadly virus that circulates in birds and has the potential to genetically mutate and jump between species to infect humans who lack immunity.

In 2004, the U.S. government stockpiled 20 million doses of vaccine against the “Vietnam” strain of the virus, which was then the dominant strain, reports. The avian flu changes rapidly, however, and a different strain, the “Indonesia” strain, has gained dominance.

Researchers studied vaccines for both strains in their research and measured the body’s immune response to different combinations. They also looked at different times to wait between a first and second dose.

The scientists found that two doses provided optimal coverage against H5N1, according to Giving the stockpiled Vietnam avian flu prepared the body so that a follow up dose of the Indonesia avian flu vaccine triggered an even greater immune response than the Indonesia avian flu vaccine alone. The immune response became even greater as the injections were placed further and further apart.

"The longer 180 day interval between priming and boosting vaccine doses gave the best antibody responses, although in a fast-moving pandemic, this is unlikely to be an option," Belshe said, according to "The most surprising thing we discovered was the value of time. It's incredible how much stronger response you get at six months. There's something going on there that we know nothing about and is a very interesting area for future research."