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Officials Say Flu Pandemic Is Around The Corner

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Officials Say Flu Pandemic Is Around The Corner

Global Health

Officials Say Flu Pandemic Is Around The Corner

Officials Say Flu Pandemic Is Around The Corner

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The swine flu virus has spread to at least 20 countries. Experts are now worried that pigs may start to get infected by humans with the virus. Top health officials are expecting a flu pandemic.


It's MORNING EDITION from NPR News. Good morning, I'm Steve Inskeep.


And I'm Renee Montagne.

Mexico's official swine flu count went up over the weekend to nearly 600 confirmed cases and more than 20 deaths. Still, that's fewer deaths than many health experts feared just a few days ago. The new flu virus has so far spread to around 20 countries, and there is a new concern that humans might start passing the virus on to pigs.

NPR's Richard Knox has more on why top officials expect a flu pandemic of some sort is upon us.

RICHARD KNOX: Yesterday on CBS's "Face the Nation," Janet Napolitano, the secretary of Homeland Security said it straight out: A pandemic has begun. The World Health Organization hasn't declared it yet. In the past week, the WHO pushed up the needle on its flu pandemic alert meter from 3, to 4, to 5. Five means a pandemic is imminent. Napolitano says people need to understand what that means.

Secretary JANET NAPOLITANO (Department of Homeland Security): When the World Health Organization goes from 3 to 4, or 4 to 5 and so forth, that doesn't associate with the severity of the disease. What it means is how widespread it is. So when you talk about level 6 - which they very well could go to this week - all that means is it's widespread throughout the world.

KNOX: Indeed, it is. It's a textbook case of how a new flu virus can spread all over the globe in the jet age. What's happening in Spain might trigger the declaration of a pandemic. Cases there now number 40. Thirty-eight of them involve people who apparently got the virus in Mexico, but the other two raise the question of whether it's spreading in Europe as it is in North America. In the daily update from the Centers for Disease Control and Prevention, Dr. Anne Schuchat says the virus has probably found its way to every corner of the United States.

Dr. ANNE SCHUCHAT (Center for Disease Control and Prevention): When I say that this virus is widespread, I mean that it is in many places, that virtually all of the United States probably has this virus circulating now. That doesn't mean that everybody's infected, but within the communities, the virus has arrived.

KNOX: Schuchat doesn't share Mexican officials optimism that a corner has been turned on swine flu.

Dr. SCHUCHAT: The time course here in the United States is later. We believe we're just on the upswing here and that in several parts of Mexico, cases began quite a while ago, several weeks ago. From what I know about influenza, I do expect more cases, more severe cases and I do expect more deaths.

KNOX: The severity of this new disease is the biggest unknown. At least 30 Americans are hospitalized with severe cases of the new flu, which officials call H1N1 of 2009. That's a small number compared to the hundreds of thousands hospitalized by regular flu. But, Schuchat says…

Dr. SCHUCHAT: One important difference between what we're seeing in hospitalizations here in the U.S. so far is that, in general, they're not in the age groups that typically are hospitalized for seasonal flu.

KNOX: Seasonal flu mostly puts infants and elderly people into the hospital, not young adults. Still, the other 200 or so cases are mild, says Dr. Marc Lipsitch of the Harvard School of Public Health.

Dr. MARC LIPSITCH (Epidemiology, Harvard School of Public Health): That's certainly good news for suggesting that severity is lower than it might have appeared. We still don't know for sure where it falls out in terms of comparisons to seasonal flu or prior pandemics.

KNOX: Experts are disturbed about something that happened recently in Alberta, Canada. A worker at a pig farm came back from a Mexican trip, and suddenly 220 pigs caught the flu, apparently from the human. Tests on some pigs reveal the same virus that's been infecting humans. Scientists say the virus originated in swine. Joan Nichols is an expert on swine flu viruses at the University of Texas in Galveston. She says the Canadian episode is alarming to animal health people.

Professor JOAN NICHOLS (Internal Medicine, University of Texas): They're going to really move to a higher level overall.

KNOX: What does that mean? What would they be saying, you suspect?

Prof. NICHOLS: Evaluating whether or not we're seeing more in pigs and then more careful precautions for people who work around pigs, to make sure they don't transfer the virus to the pigs as they work with them, nor do we transmit back again from the pigs back to people.

KNOX: That's not just a problem for pig farmers. Because pigs can get infected with both animal and human flu viruses, they create ideal conditions for mixing up viral genes. Nichol says once these viruses starts circulating, they usually become more easily transmitted over time. But nobody knows whether they also become nastier. Not much is known, she says, about the genes that do that in human flu viruses.

Richard Knox, NPR News.

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New Strain May Edge Out Seasonal Flu Bugs

Nurses care for victims of the 1918 "Spanish flu" pandemic during an outdoor fresh air cure in Lawrence, Mass. Hulton Archive/Getty Images hide caption

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Hulton Archive/Getty Images

Nurses care for victims of the 1918 "Spanish flu" pandemic during an outdoor fresh air cure in Lawrence, Mass.

Hulton Archive/Getty Images

'Flu Shots' Blog

Get the latest updates on the swine flu outbreak.

In Focus

Richard Harris Reports On The Flu's Evolution On Morning Edition

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Biologists say there's a good chance that the emerging flu strain could establish itself as the dominant strain of influenza in future flu seasons.

Three times in the last century, a substantially new flu virus has emerged and displaced the existing strains. That's quite different from the usual pattern, in which the circulating virus mutates just enough to keep vaccine makers tweaking their annual product.

"You can think of those strains, that vary from year to year, as though they were cousins in the same family. They are variations on a theme," says William Schaffner at Vanderbilt's medical school. But he says the emergence of this new virus is different. This virus, which originated partly in pigs, could be a game-changer.

"This one is completely new," Schaffner says. "This one is a stranger in town. We've never seen one like this before."

Pandemic Strains Become Dominant

The new swine flu virus has continued to spread, with more than 1,200 confirmed cases and 27 deaths worldwide. All but one of the fatalities occurred in Mexico, where officials decided Monday to allow most businesses to reopen Wednesday.

In the U.S., the number of confirmed cases stood at 310 in 37 states as of Monday evening.

The new swine flu virus is not merely a case of the usual gradual evolution. The big change scientists have seen with this strain is called a "shift."

The most infamous shift was the virus that appeared in 1917 and caused the deadly flu pandemic of 1918. That virus then became the dominant variety of flu for several decades. Then in 1957, it was displaced by another shift virus.

There was yet another shift in 1968, says Stephen Morse at Columbia University's Mailman School of Public Health.

"There does seem to be a rule of thumb about this, which is that every pandemic in the 20th century essentially established the variants that would become the circulating seasonal influenzas until the next pandemic came along to displace them," Morse says.

Each shift led to a stronger-than-usual flu season, but each one also calmed down after a year or two, once the population became exposed to the new viruses or were vaccinated. Morse says the question now is whether the new H1N1 swine virus will keep moving from person-to-person efficiently.

"If it continues like that, we'll expect to see this virus chugging along, and probably the next seasonal influenza will be a descendent of this one," Morse says.

Distant Cousins Provide Some Protection

The question, then, is how nasty the virus will end up being. Professor John Oxford at St. Bart's and the Royal London Hospital says there's some reason for cautious optimism.

"In one sense, it's one of the mildest shifts because most people on the planet have got some memory, have come across H1N1 viruses since 1978," Oxford says.

Even though health officials are calling this new virus H1N1, that's also the type of virus that's in wide circulation today. And it has an interesting history. It was the dominant flu virus through the 1920s, '30s and '40s. Oxford says it disappeared in 1957, when it was displaced by another flu virus. But then a strain of H1N1 suddenly reappeared in 1977.

"Now where could it have come from?" he asks. "We reckon now, in retrospect, it was probably released accidentally from a laboratory, probably in northern China or just across the border in Russia, because everyone was experimenting with those viruses at the time in the lab."

It was nothing malicious, Oxford believes, just some flu vaccine research that broke out of containment. The descendents of this virus are still circulating. He notes that most people who have encountered the newly emerged H1N1 virus seem to have developed only mild disease, and he speculates that's because we have all been exposed to a distant cousin, the H1N1 virus that emerged in the 1970s.

"That escaped virus perhaps will provide some benefit now in the face of this pig thing," Oxford says.

This is well-informed speculation, not iron-clad assurance. And there is another less reassuring lesson from the previous big shifts in flu viruses. They caused mild disease when they first appeared in the spring, but they all caused big flu seasons when they returned in the fall as the new dominant virus. That's one reason that health officials are taking the new virus very seriously.

NPR wire services contributed to this report.