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MD: Avian flu must mutate for it to sicken humans

Multiple mutations foster guesswork about possible pandemic


World Health Organization (WHO)
Bird flu

(CNN) -- A physician monitoring the threat of avian influenza says a key question is whether the strain of bird flu in Asia has mutated into a flu that could result in a human pandemic.

Dr. Marc Siegel, author of "False Alarm: The Truth About the Epidemic of Fear," said it's likely that such a pandemic could occur "over the next 50 years and maybe even over the next 10 or 20," but he said "it may very well not be this bug."

The first case of avian influenza type A (H5N1) spreading from a bird to a human was recorded in Hong Kong during a 1997 outbreak of the flu in poultry, according to the Centers for Disease Control and Prevention in Atlanta, Georgia. (Watch why many companies aren't interested in making vaccine -- 1:29)

Siegel said there are still many unanswered questions regarding whether this strain of bird flu could be a pandemic trigger. "If it does mutate or another one does, we don't know for sure what it will do," he said. "That's, you know, really speculation at this point."

In addition to Asia, unspecified strains of avian flu have been detected or suspected among birds in Romania, Turkey, Russia and Kazakhstan. (Full story)

Because bird flu viruses are constantly changing, health officials warn that they could adapt over time to infect and spread among humans.

That has already happened in Asia. Since December 2003, the H5N1 strain of bird flu has turned up in at least 10 Asian countries, infecting more than 100 people, killing at least 60 of them.

It is believed to have spread when humans came in contact with an infected bird or a contaminated surface, according to the CDC. Human to human spread of the virus is rare and has not continued beyond one other person, the CDC said.

On September 29 the World Health Organization warned that an avian flu pandemic among humans was "imminent" and urged all nations to make preparations for battling an outbreak.

U.S. health officials are drafting preliminary plans to deal with a possible outbreak.

Siegel, an associate professor at New York University School of Medicine, said the world health community must improve vaccine mass production. Current manufacturing technology is about 50 years old and involves creating vaccines in fertilized chicken eggs.

"We can use genetic engineering and get a vaccine very quickly, but we are busy using the old chicken-egg medium which takes three to six months to make a vaccine," he said. "I think we need to upgrade our ability to make vaccines quickly."

A flu strain might mutate again before vaccines can be manufactured and quickly could be obsolete.

"If we stockpile vaccine against a bug that doesn't affect us directly we may end up having to discard it," Siegel said.

U.S. Secretary of Health and Human Services Mike Leavitt said Thursday the world is "woefully unprepared" to respond to a pandemic. He said the United States must "have surveillance domestically, so if it shows up here we know about it very quickly."

In addition to techniques and time factors involved, commercial manufacture of vaccines often isn't profitable, Siegel said, and "it's hard to get the manufacturers excited about it."

On Friday, White House officials met with representatives of the U.S. pharmaceutical industry to encourage them to get involved in the manufacture of flu vaccine.

While the world needs to prepare for a worst case scenario, Siegel said, it's important not to create panic about the threat of avian flu.

"We're wise to be prepared, but we are not wise if we worry unnecessarily about something that may not happen here," he said.

Researchers announced Wednesday that they had reconstructed the 1918 strain of flu virus, a major advancement that could speed up preparation for -- and potentially thwart -- a pandemic. (Full story)

It marked the first time an infectious agent behind a historic pandemic has ever been re-created.

At the end of October, Australia is set to host a meeting of the 21 members of the Asia-Pacific Economic Cooperation group, where pandemic and disaster management coordinators will discuss the region's response to the threat. (Full story)

Canada will host an October 25-26 meeting of high-level public health officials in Ottawa. And WHO has called for a November 7-8 meeting in Geneva, Switzerland, to coordinate needed funding.

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