WHO declares first flu pandemic in 41 years

The World Health Organization scaled up its flu warning to its highest level Thursday, declaring the first global influenza pandemic in 41 years as cases of H1N1 continued to mount in the USA, Europe, Latin America and Australia.

"The scientific criteria for a pandemic have been met," said Margaret Chan, director general of the WHO. "The world is now at the start of the 2009 influenza pandemic."

The decision marks the agency's formal recognition of the magnitude of the challenge posed by a novel, H1N1 flu virus now spreading unchecked among people who, because the virus is new, are virtually all susceptible to it.

The WHO is working closely with vaccine makers, who are just wrapping up production of seasonal flu vaccine for fall and gearing up to produce the first doses of an H1N1 vaccine by September. The agency urged member nations to maintain their vigilance to detect ominous changes in the virus's behavior and, if the virus is widespread, to focus on caring for patients.
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Although Chan described the pandemic as "moderate in severity," she stressed that flu pandemics are unpredictable. "The virus writes the rules," she said. "This one, like all influenza viruses, can change the rules without rhyme or reason, at any time."

On Thursday, the WHO said 74 countries had reported nearly 28,774 cases of H1N1 flu, including 144 deaths.

H1N1, better know as swine flu, has continued to spread during the start of summer in the Northern Hemisphere. Normally, flu viruses disappear with warm weather, but so few people have developed immunity to the new virus, it continues to smolder, especially in New England, New York and New Jersey.

Centers for Disease Control and Prevention Director Thomas Frieden, who orchestrated New York City's response to the epidemic as health commissioner until he took over the CDC this month, said public health officials from Miami to Seattle long ago set in motion all of the appropriate steps for responding to a pandemic.

"This is not a surprise," he said. "It was expected based on the data."

He echoed Chan's assessment that the WHO announcement is more a reflection of the epidemic's geographic reach than the virus's virulence. "This doesn't mean there's any difference in the level of severity of flu," he said. "This is not a flu that is anywhere near as severe as the 1918 flu, for example."

Frieden said federal, state and local health officials have worked for years to prepare for a pandemic that many believed was inevitable. They have bought millions of doses of antiviral drugs for national stockpiles, prodded makers to vastly increase their capacity to produce flu vaccine and staged desk-top simulations to explore the best strategies for coping with an epidemic. State and local health officials are planning a series of regional meetings to discuss how best to respond to the pandemic as it evolves.

"When you're talking about pandemic influenza, you're talking about a marathon not a sprint," said the WHO's top flu expert, Keiji Fukuda.

Fortunately, most cases of the H1N1 flu run their course without complications. Most patients require no medical treatment, but about 2% of patients develop severe disease, often life-threatening pneumonia. Most deaths have occurred in adults between the ages of 30 and 50, a marked change from seasonal influenza when most deaths occur in fragile elderly people, Chan said.

Most of those who have died suffer from underlying illnesses, including asthma, heart disease, diabetes, obesity and immune deficiencies. So far about 8% of 13,217 patients in the USA have had to be hospitalized, according to statistics from the CDC.

Frieden noted that common-sense precautions can not only help reduce the spread of the disease, but also save lives. He urged people to "stay home if you're sick. Cover your mouth when you cough. For those who become sick, seek care promptly," noting that rapid treatment with antiviral drugs "makes a difference."

Anyone with an underlying chronic illness plus a fever of at least 100.4 degrees and a cough or a sore throat should consult a doctor, he said. Women who are pregnant and infants under age 2 are also at risk and should see a doctor if flu symptoms arise.

"Although we have not seen large numbers of severe cases in this country so far, things could possibly be very different in the fall, especially if things change in the Southern Hemisphere, and we need to start preparing now in order to be ready for a possible H1N1 immunization campaign starting in late September," said U.S. Department of Health and Human Services Secretary Kathleen Sebelius.

Ann Schuchat of the CDC said the federal government so far has allotted nearly $1 billion for vaccine development and clinical trials. So far, the Department of Health and Human Resources has placed orders with five manufacturers for $650 million worth of vaccine for the new virus along with $280 million of a booster to increase its potency, if necessary.

The last pandemic — the Hong Kong flu of 1968 — killed about 1 million people worldwide. Ordinary flu kills about 250,000 to 500,000 people worldwide each year.