The Centers for Disease Control and Prevention Announces New HIV Incidence Estimates for the United States

Dear Colleague:

The Journal of the American Medical Association (JAMA) released the first HIV incidence estimates from a new national surveillance system -- the first of its kind in the world that is based on direct measurement of new HIV infections. Monitoring trends in HIV incidence (the number of new infections in a given year) in the United States has historically posed a challenge, in part, because many HIV infections are not diagnosed until years after they occur -- which has made it difficult to precisely identify and clearly define the leading edge of the epidemic.

The release of these new incidence estimates is a significant sentinel event in the HIV/AIDS epidemic because the clarity this system provides means we now have much more information about the current status of the epidemic. In coming years, this new system will provide trend information that will allow us to better monitor the course of the epidemic and assess the impact of our nation's HIV prevention efforts. The use of this new CDC-developed technology makes the following possible: (1) better targeting of prevention programs, (2) more precision with which to measure and evaluate progress, and (3) more specific information to inform resource allocation decisions.

The estimates from our nation's new HIV incidence surveillance system reveal that the U.S. epidemic is -- and has been -- worse than previously estimated and serve as a wake-up call for all Americans. Using the new technology called Serological Testing Algorithm for Recent HIV Seroconversion (STARHS) that distinguishes recent from longstanding HIV infections, CDC estimates that 56,300 new HIV infections occurred in the United States in 2006. Prior to the availability of STARHS, CDC previously estimated that approximately 40,000 new HIV infections occurred annually since the 1990s. It is important to note that the 2006 estimate does not represent an actual increase in the annual number of new infections; rather, a separate CDC historical trend analysis published alongside the incidence estimate suggests that the number of new HIV infections was never as low as 40,000 and has been roughly stable since the early 2000s. Even though the analysis shows overall stability in new HIV infections in recent years, the HIV/AIDS epidemic remains at an unacceptably high level.

The 2006 HIV incidence estimates show:

• Gay and bisexual men of all races remain the group most heavily affected by HIV, accounting for 53% of all new infections.

• The impact of HIV is greater among blacks than any other racial or ethnic group, with an HIV incidence rate that is 7 times higher than that of whites (83.7/100,000 for blacks compared to 11.5/100,000 for whites) and almost 3 times higher than that of Latinos (29.3/100,000).

Overall, levels of HIV infection in the U.S. are too high and have been increasing among men who have sex with men (MSM) since the early 1990s. The HIV epidemic must not continue on its current course. With more people living with HIV than ever before, there are more opportunities for transmission; however, the number of new infections has remained relatively stable. The estimates indicate that HIV infections have been relatively stable to declining among people who inject drugs, women of all races, and high-risk heterosexuals. While this is an important sign of success, the new estimates underscore the need to accelerate progress.

We have significant evidence that prevention works. HIV counseling and testing reduce risk behaviors and help link persons living with HIV to medical care and treatment. Behavioral and social interventions significantly reduce risk behaviors and sexually transmitted infections among at-risk and HIV-infected persons. The effectiveness of HIV prevention has been repeatedly shown in multiple scientific reviews.

The stability in new HIV infections indicates that prevention efforts are reaching many individuals living with HIV/AIDS and that most are taking steps to protect themselves and their partners. But the fact remains that many populations at risk are not being reached by our prevention efforts, and much more must be done. For example, recent data indicate that in the past year, 80% of MSM have not been reached by the intensive interventions we know to be most effective. This illustrates one of the many challenges to preventing the spread of this disease -- the challenge of reaching new generations while adapting to the evolving epidemic. Perceptions of risk and treatment options change over time, and we must work together to ensure that prevention barriers such as complacency, stigma, and substance abuse do not allow this disease to continue to flourish. Additionally, far too many undiagnosed individuals remain -- 25% of persons living with HIV are unaware of their status and account for more than half of all new HIV infections.

These findings serve as a wake-up call for the United States. They underscore the need to reach all populations at risk for HIV with effective prevention programs and serve as an urgent reminder that we all -- as individuals, communities, and as a nation -- need to do more to prevent the further spread of HIV and its devastating effects on our communities.

For more information on the 2006 HIV incidence estimates including CDC's podcasts, frequently asked questions and answers, fact sheets, and related surveillance information, please visit "HIV Incidence in the United States."

Thank you for all you do in support of HIV prevention.

Sincerely,

Richard Wolitski, Ph.D.
Acting Director,
Division of HIV/AIDS Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention