For the first time since the height of the AIDS epidemic in the 1980s, more than a million Americans are believed to be living with the virus that causes AIDS, the government said Monday.

The latest estimate is both good and bad news -- reflecting the success of drugs that keep more people alive and the failure of the government to "break the back" of the AIDS epidemic by its stated goal of 2005.

The Centers for Disease Control and Prevention said that between 1,039,000 and 1,185,000 people in the United States had HIV in December 2003. The previous estimate, from 2002, showed that between 850,000 and 950,000 people had the AIDS virus.

The jump reflects the role of medicines that have allowed people infected with the virus to live longer, said Ronald Valdiserri, deputy director of the CDC's National Center for HIV, STD and TB Prevention. "While treatment advances have been an obvious godsend to those living with the disease, it presents new challenges for prevention," he said.

The challenges include overcoming a failure by the government to meet its 2005 goal of cutting in half the estimated 40,000 new HIV infections that have occurred every year since the 1990s. CDC officials previously have said the country's HIV infection rate has been "relatively stable" and without change. As the National HIV Prevention Conference was set to begin this week, Valdiserri said no new infection data will be available until next year.

However, recent outbreaks of HIV and sexually transmitted diseases in major cities offer a hint that new infections may be as high as 60,000 cases a year, rather than the government estimate of 40,000, said Carlos del Rio, an Emory University professor of medicine. "The U.S. has had a clear failure in HIV prevention -- I think the increase in prevalence is a reflection of that, of the poor job we do in HIV prevention," del Rio said.

He said the CDC has not been given adequate resources to tackle HIV prevention and that experts have focused too much on whether it is better to promote abstinence or condom use to stop the spread of the virus. "We're debating too much what to do and are not doing enough," he said.

Estimating the number of Americans with HIV has always been a difficult task for health officials, but this year's figures are believed to be the most accurate ever thanks to wider case reporting.

The CDC's latest estimates indicate blacks account for 47 percent of HIV cases; gay and bisexual men make up 45 percent of those living with the virus that causes AIDS, the health agency believes.

The CDC warned that those demographics may soon change because heterosexual blacks, women and others infected after having high-risk sex account for a larger proportion of those living with HIV than those who are living with full-blown AIDS.