Health officials on Tuesday released figures for H1N1 flu (also known as swine flu) hospitalizations and deaths for the seven weeks since the beginning of September. The information comes from 28 states.
It showed more than half of all hospitalizations were people 24 and younger; more than a quarter were ages 5 to 18 years.
"Essentially, this is still a young person's disease," said Dr. Anne Schuchat of the Centers for Disease Control and Prevention.
H1N1 flu deaths were concentrated in young and middle-aged adults. A third of all deaths were people ages 25 through 49; another third were 50 to 64.
Only 12 percent of deaths occurred in elderly. That's a stark contrast to the roughly 90 percent of deaths in the elderly from seasonal flu, Schuchat said at a Tuesday press conference.
"It's almost completely reversed," said Schuchat, who heads the CDC's National Center for Immunization and Respiratory Diseases.
The figures are similar to what the CDC saw in the spring, she said.
Many people 55 and older have some degree of immunity to the H1N1 flu virus, perhaps from exposure decades ago to a similar virus or vaccine. But the ability of the H1N1 flu virus to attack deep in the lungs seems to also make it more dangerous to some of the younger people who are infected, CDC officials say.
The latest figures show about 5,000 hospitalizations in 27 states for lab-confirmed H1N1 flu, and about 300 deaths in 28 states. Not all states report lab-confirmed H1N1 flu cases to the CDC; some report "influenza-like illnesses" that may include cases caused by other kinds of viruses.
The count did not include a breakdown of how many were pregnant or had other health problems that put them at higher risk for severe complications.
The CDC confirmed a downward trend of H1N1 in parts of the Southeast but warned against complacency, reports CBS News medical correspondent Dr. Jon LaPook. The agency has been studying the 1957 Asian flu, which appeared to taper off by December that year, but roared back in a second wave during the spring of 1958.
"There's a lot about the fall of 1957 and the spring of 1958 which causes us to be paying attention," Schuchat said. "There was a very impressive wave of disease in the spring."
The CDC does not have an exact count of all the U.S. H1N1 flu deaths and illnesses since the virus was first identified in April, but the agency says more than 800 have died, including at least 86 children. Millions of Americans have been infected, although many probably suffered only mild illness, CDC officials say.
Concerns over Vaccine Logistics
The CDC said today it has a stockpile of close to 13 million vaccine doses, nearly 11 million of which have been ordered by various state governments.
But CBS News correspondent Don Teague reports that some cities across the country - like Dallas - don't have enough vaccine to go around.
Health officials say more than 600,000 people in Dallas County should get vaccinated against H1N1 but only 700 doses have made it to Dallas County's Health Department, Teague reports. Officials are still trying to determine which of the highest risk groups should be vaccinated first.
"This is the time when we have the most flu going on in our community right now, there's a lot of illness right now that could be prevented with the vaccine; unfortunately it's not available yet," said Dallas County Medical Director Dr. John Carlo.
Federal health officials say there isn't actually a shortage of vaccine but it hasn't always made it to the right place at the right time.
Teague reports that in Nampa, Idaho, more than 2,200 doses came in this past weekend and were gone in a day; in southwest Washington State health officials expected 19,000 doses, but are only getting 5,000 this week.
On the other hand, Teague reports, it's more supply than demand in Las Vegas and at one clinic in Miami, they've received significantly more doses than they've given out.