Swine flu is "a younger person's disease," with more than half of hospitalizations and nearly a quarter of deaths from H1N1 involving people under the age of 25, a top health official said Tuesday.
Fifty-three percent of nearly 4,900 laboratory-confirmed cases of swine flu between September 1 and October 10 involved patients under the age of 25, Anne Schuchat, an expert on respiratory diseases and immunization at the Centers for Disease Control and Prevention (CDC), told reporters.
Almost a quarter of the 292 deaths from swine flu which were reported in the same time period were in young adults, teens and children, and two-thirds of deaths from H1N1 were in the 25-64 age group, Schuchat said.
"This is dramatically different than what we see with seasonal flu" where 90 percent of fatalities and 60 percent of hospitalizations occur in people 65 and over, said Schuchat.
Only 12 percent of fatalities and seven percent of hospitalizations for swine flu have involved patients aged 65 and over.
H1N1 flu is "still a younger person's disease," and because it is disproportionately affecting young people, they have been made a target population for the massive vaccination effort that is being rolled out across the United States, Schuchat said.
As of Monday, 12.8 million doses of H1N1 vaccine were available, and the vast majority of those doses -- 10.8 million -- have been ordered by the states.
That meant there were three million more doses available this week than last, when the effort to vaccinate anyone who wants to be innoculated against H1N1 flu began in earnest.
Schuchat hailed as "a significant achievement" the fact that a steady supply of what she called safe, effective vaccine continues to flow out to health officials around the United States.
"Orders are being filled quickly. Vaccine is being given out all around the country," she said.
"This is a significant achievement, to have what we believe is a safe and very effective vaccine available in our states and counties... just since the April recognition of this virus," she said.
At least 4,735 people have died from swine flu infections since April, when an outbreak of H1N1 flu was first reported in Mexico, the World Health Organization has said.