WHO starts process of developing human vaccine to BC avian flu strain
HELEN BRANSWELL
Canadian Press
Tuesday, April 06, 2004
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(CP) - The World Health Organization is starting the process of producing a human vaccine for the H7 avian flu virus ravaging poultry stocks in British Columbia and Canada's National Microbiology Laboratory will be one of the centres working on the project.
Dr. Frank Plummer, the lab's scientific director, confirmed Tuesday the Winnipeg facility will be one of at least two labs in the world that will try to develop what's called a viral seed - a genetically modified version of the H7 virus that could be used by commercial vaccine makers should the H7 strain emerge as a pandemic strain.
That appears unlikely at this point, but nevertheless national and international health authorities have to prepare for the possibility. It's also good practice for when the next pandemic - believed by influenza experts to be inevitable - comes, Plummer said.
"In some ways we're treating it like that," he said in an interview from Winnipeg. "It's part of (pandemic) preparedness."
Producing a seed vaccine for an H7 virus requires the capacity to use reverse genetics, a procedure in which the part of the virus which is deadly to chickens is plucked out. Vaccines are grown in fertilized eggs; unless an H7 virus is modified, it would kill the embryos and arrest the process.
If all goes well the process should take between four and six weeks, Plummer said.
Plummer confirmed the national lab would provide the WHO with samples of the viruses taken from the two people who were infected with the H7 virus in British Columbia. Those samples were sent off to the national lab Tuesday by the British Columbia Centre for Disease Control in Vancouver.
WHO pandemic planning guidelines require the organization to commence production on a human vaccine for an avian influenza strain once there is evidence two people have been infected in an outbreak, a spokesperson for the Geneva-based organization explained.
"We had to do it. You have two human cases. Zip! It's automatic," said Dick Thompson, communications director for the communicable diseases branch.
Thompson admitted the project likely will not proceed with the same level of urgency that surrounded efforts to develop a seed vaccine for the H5N1 strain that has killed 22 of 33 people infected during an extensive outbreak in Asia earlier this year.
"Do we feel a sense of urgency about this? Well, no. It just isn't as serious to us as what had happened in Asia, for lots of reasons," Thompson said.
"You guys have the resources to deal with this. There's rapid and transparent reporting . . . so you know where the disease is. There's not a lot of argument about how to get rid of the infected birds. You're moving ahead with mass culling which is exactly what should be happening. . . . You have trained workers that are being given the right personal protection equipment."
"And so you've got a virus that seems to cause relatively minor disease so far in a situation where there's widespread knowledge and an abundance of resources to deal with the problem."
The H7 strain hasn't proved to be as serious a threat to human health as the H5N1 strain, though one person died in a large H7 outbreak in the Netherlands last spring during which at least 89 people were infected.
The Dutch outbreak was caused by an H7N7 strain. The two Canadian cases are believed to be a different strain of influenza, H7N3. Confirmation of the neuraminadase or N factor in the human cases will be done at the Winnipeg lab, said virologist Martin Petric of the B.C. disease control centre.
Another lab that will likely be involved in the project is the influenza lab at St. Jude Children's Research Hospital in Memphis, Tenn.
"Certainly if we're asked as part of a WHO effort, we're certainly willing to do whatever is needed from us," said Dr. Richard Webby, who is leading an effort there to produce a viral seed for the H5N1 influenza strain.
Late last week Thompson revealed that one of three laboratories working to develop a prototype vaccine for the H5 virus had succeeded. A British government lab, the National Institute for Biological Standards and Control, will announce this week that it has completed that task.
© Copyright 2004 The Canadian Press
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