WASHINGTON (AP) - As the swine flu outbreak strikes the U.S. early and hard, health officials note a worrisome number of child deaths and warn that supplies of vaccine will remain scarce for at least the next couple of weeks.

Delays in producing the vaccine mean 28 million to 30 million doses, at most, will be divided around the country by the end of the month, not the 40 million-plus states had been expecting. The new count from the Centers for Disease Control and Prevention means anxiously awaited flu-shot clinics in some parts of the U.S. may have to be postponed.

It also delays efforts to blunt increasing infections. Overall, what CDC calls the 2009 H1N1 flu is causing widespread disease in 41 states, and about 6 percent of all doctor visits are for flu-like illness - levels not normally seen until much later in the fall.

Federal health officials said Friday 11 more children have died in the past week because of the virus.

The Centers for Disease Control and Prevention says about half of the child deaths since September have been among teenagers.

And overall for the country, deaths from pneumonia and flu-like illnesses have passed what CDC considers an epidemic level.

"These are very sobering statistics," says the CDC's Dr. Anne Schuchat.

This new strain is different from regular winter flu because it strikes the young far more than the old, and child deaths are drawing particular attention. Eighty-six children have died of swine flu in the U.S. since it burst on the scene last spring - 43 of those deaths reported in September and early October alone, said Schuchat.

That's a startling number because in some past winters, the CDC has counted 40 or 50 child deaths for the entire flu season, she said, and no one knows how long this swine flu outbreak will last.

Also in contrast to regular winter flu, swine flu sometimes can cause a very severe viral pneumonia in otherwise healthy young adults, the World Health Organization warned.

Typically, influenza weakens people so they're vulnerable to bacterial pneumonia, especially those over age 65. But the new H1N1 can dive deeper into the lungs, in "small subsets" of patients who go into respiratory failure within days, said WHO medical officer Dr. Nikki Shindo.

"Do not delay the treatment," she said as WHO ended a three-day meeting of 100 international flu specialists gathered in Washington.

The new swine flu strain also may have hit some pigs at the Minnesota State Fair in late August, animals possibly infected by some sick 4-H students. If the infection is confirmed, it wouldn't be a surprise: A sick farm worker first infected pigs in Canada last spring, and herds have been hit in Australia and Argentina, too. The virus doesn't spread to humans who eat pork.

Fortunately, most people recover from the new strain with simple at-home care, just as with the regular flu. While there aren't precise counts, states have reported more than 2,000 deaths from pneumonia or flu-like illnesses to the CDC since Aug. 30. And Schuchat said other tracking systems show those deaths have reached the level that each year is used to declare an influenza epidemic, months early.

As of Wednesday, states had ordered 8 million of the 11.4 million doses of swine flu vaccine the government has ready to ship. Just over half of the vaccine now available is in shot form and the rest as a nasal spray. First in line for scarce H1N1 vaccine are supposed to be pregnant women, anyone age 6 months to 24 years, health care workers and people under 65 with flu-risky conditions.

CDC's Schuchat urged patience, saying eventually enough vaccine will be here for everyone who wants it.

Regular winter flu kills 36,000 Americans a year, and around the country some clinics aren't getting shipments of seasonal vaccine as quickly as expected either, as manufacturers juggle the extra work. About 82 million doses of seasonal vaccine have been shipped, and 114 million eventually will arrive, enough for typical demand, Schuchat said.

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Flu info: http://www.flu.gov