Swine flu was widespread in only 14 states last week - mostly in the Northeast. That's down from 25 states the week before and 48 in late October. The Centers for Disease Control and Prevention released the new data Friday.
CDC officials said a shortage of swine flu vaccine is easing, with 85 million doses now available. About 98 percent of lab-confirmed influenza cases last week were swine flu, but the CDC also noted seasonal flu is increasing slightly.
The regular flu usually peaks in the winter.
Special Report: H1N1 Virus
Even though new infections seem to be receding, the CDC is urging people not to forget about immunization. Last month at the Dallas County Health Department, 3,000 people poured in daily for vaccine. That's now down to a trickle.
On Thursday, CDC released estimates that H1N1 flu has sickened nearly - 50 million - and killed nearly 10,000.
Officials also estimate that around 200,000 people have been hospitalized since the virus was first identified in April through mid-November. That's the same amount that occurs normally in an entire flu season.
Previously, the CDC estimated that about 22 million people came down with H1N1 from April to mid-October, reports CBS News medical correspondent Dr. Jon LaPook. In the space of four weeks, that number jumped to 47 million, the vast majority under age 65.
Children and young adults have been one of the hardest-hit groups. An estimated 1,100 children have died from H1N1.
"Many times more children and younger adults, unfortunately, have been hospitalized or killed by H1N1 influenza than occurs during a regular flu season," said CDC Director Tom Frieden.
In a typical flu season, about 20,000 children are hospitalized. Already in the first seven months of the H1N1 outbreak, 71,000 have been hospitalized, LaPook reports.
Dr. John Carlo is worried the virus isn't done yet.
"We're really going to be concerned about what the rest of the winter is going to be like," Carlo told LaPook. "We have to be ready for what's going to happen in February and March."