Viruses in H7 family prove resistant to vaccines developed so far
The Canadian Press
Posted: Apr 12, 2013
Making a vaccine to protect against the new H7N9 flu virus that has emerged in eastern China could prove to be problematic, influenza experts acknowledge.
There hasn’t been enough time to produce even the seed strain to make H7N9 vaccine, let alone small batches of a prototype vaccine for testing. So researchers haven’t had a chance to see how a vaccine against this new flu strain might work in people.
But clinical trials of vaccines made to protect against other viruses in the H7 family have shown the vaccines don’t induce much of an immune response, even when people are given what would be considered very large doses.
“In all cases where these vaccines were trialed, it was found that the vaccines were poorly immunogenic,” said Nancy Cox, the virologist who heads the influenza branch at the U.S. Centers for Diseases Control in Atlanta.
“And so this is a signal that we might be facing challenges with producing an immunogenic vaccine using this particular virus. But that remains to be determined.”
Cox and CDC flu expert Dr. Tim Uyeki touched on the potential problem in a perspective article on the H7N9 situation published online Thursday by the New England Journal of Medicine.
The perspective accompanied an article by Chinese clinicians describing the first three H7N9 infections that came to light in their country. The article outlines how sick the patients became — in a word, very — and what the genetic sequences of the viruses recovered from them indicate about the path H7N9 took through nature to get to people.
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