Research Suggests Strategy for Stockpiled Avian Flu Vaccine

(Agricultural Research Service, USDA)

A new study suggests that current stockpiles of avian influenza (H5N1) vaccine can be part of an effective strategy to protect against a new pandemic, even though the vaccine was developed for an earlier strain of the virus. The researchers from three universities, the Mayo Clinic in Minnesota, Group Health Research Institute in Washington state, and EMMES Corporation in Maryland published their findings in the current (March 2011) issue of the Journal of Infectious Diseases.

Avian flu is an infectious virus that circulates in birds and has the potential to genetically mutate and jump between species to infect humans. Because people lack immunity to the virus, public health officials are concerned that the virus can spread quickly to become a pandemic outbreak.

In anticipation of a bird flu pandemic in 2004, the U.S. government stockpiled 20 million doses of vaccine against the dominant strain of the virus at the time, the “Vietnam” strain. But the avian flu virus changes quickly and now the “Indonesia” strain, has replaced the Vietnam strain as the prominent circulating avian flu.

The research team tested both strains against the Vietnam vaccine and an investigational vaccine designed to protect against the Indonesia strain in 491 healthy adults. They measured the body’s immune response to different combinations of the two avian flu vaccines, as well as the optimum length of time between giving the first and second doses of vaccine.

They found that two doses of vaccine are needed to provide protection against the avian flu. Giving the stockpiled Vietnam avian flu vaccine as the first dose primed the body’s system so that a follow up dose of the new Indonesia avian flu vaccine triggered a heighten immune response. The immune response to both strains of avian influenza became more robust as the injections of vaccine were spaced further apart.

The findings suggest public health officials can get a jump on fighting a pandemic caused by avian flu virus because they won’t have to wait for a vaccine that exactly matches the current strain of bird flu to be manufactured. Authorities can begin immunizing against the bird flu by giving an injection of the Vietnam vaccine to prime the body for a second shot of a vaccine that matches the current Indonesia strain.

Read more:

• Bird-Flu Stopping Transgenic Chickens Produced
• Fraunhofer USA Gets FDA Go-Ahead for H5N1 Vaccine Trial

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