More than 56,000 in U.S. infected with AIDS each year

The CDC stressed that actual infection rates have not risen but said better methods of measuring newly diagnosed infections and extrapolating these to the general population led to the higher estimates.

"CDC's first estimates from this system reveal that the HIV epidemic is -- and has been -- worse than previously known. Results indicate that approximately 56,300 new HIV infections occurred in the United States in 2006," the CDC said in a statement.

"This figure is roughly 40 percent higher than CDC's former estimate of 40,000 infections per year, which was based on limited data and less precise methods."

The CDC said the epidemic has been stable since the late 1990s, "though the number of new HIV infections remains unacceptably high."

"The analysis shows that new infections peaked in the mid-1980s at approximately 130,000 infections per year and reached a low of about 50,000 in the early 1990s," it said.

Dr. Kevin Fenton, who heads the CDC's AIDS branch, said 15,000 to 18,000 Americans die every year of AIDS.

"The data really confirm that there is a severe impact of this epidemic among gay and bisexual men in the United States ... as well as black men and women," Fenton said in a telephone interview.

The numbers, published in the Journal of the American Medical Association, confirm that black Americans are seven times more likely to be infected than whites.

DOING TOO LITTLE