Advance shots protect those most exposed in possible pandemic, researchers suggest
WEDNESDAY, Oct. 8 (HealthDay News) -- People can be protected against a potential avian flu epidemic by getting advance shots of a vaccine that may or may not be effective against the strain causing the epidemic, British researchers suggest.
That apparently daffy strategy is scientifically sound, according to a letter in the Oct. 9 issue of the New England Journal of Medicine, because priming people with an old vaccine would make any new vaccine work faster and better.
A study of 24 people who got a now outdated avian flu vaccine seven years ago shows the strategy would work, said Dr. Iain Stephenson, a senior lecturer in infectious disease at the University of Leicester.
Those people quickly developed flu-fighting antibodies when challenged with the H5 avian flu strain that is regarded as the one most likely to spread from birds to humans and cause an epidemic, Stephenson said.
In June, U.S. researchers reported that they had developed a bird flu vaccine that appeared to be safe and more effective than the one currently approved for human use.
Three-quarters of volunteers produced antibodies against the virus after receiving a second dose of the vaccine, CELVAPAN, made by Baxter, compared with only 45 percent in the currently approved vaccine. Baxter conducted the study.
"If there were to be a pandemic of avian influenza, a vaccine would be the principal means of protecting the public," Stephenson said. "Because most people would be naive to the strain, it would very likely take two doses to produce an immune response. It is very challenging to give two doses."
And while governments have stockpiled vaccines against the H5 strain, "there are two problems," Stephenson said. "Is that vaccine a good match to the pandemic strain? H5 changes, and the emerging strain could be distant to the
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