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HIV/AIDS Statistics and Surveillance

The NCHHSTP Atlas is an interactive tool that provides CDC an effective way to disseminate HIV, Viral Hepatitis, STD and TB data, while allowing users to observe trends and patterns by creating detailed reports, maps, and other graphics. Find out more!

The Latest Statistics and Surveillance Resources:

Surveillance is the ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event.  HIV/AIDS surveillance observes records and disseminates reports about new cases of HIV and AIDS.

CDC’S HIV/AIDS surveillance system is the nation’s source for timely information used to track the epidemic. CDC funds and assists state and local health departments to collect the information. Health departments report their data to CDC so that information from around the country can be analyzed to determine who is being affected and why. For details on confidentiality of surveillance data, see Data Security and Confidentiality Guidelines for HIV, Viral Hepatitis, Sexually Transmitted Disease, and Tuberculosis Programs: Standards to Facilitate Sharing and Use of Surveillance Data for Public Health Action.

The ultimate surveillance goal is a nationwide system that combines information on AIDS cases, new HIV infections, and behaviors and characteristics of people at high risk. By meeting this goal, CDC can track the epidemic and direct HIV prevention funding to where it is needed the most.

Tracking AIDS Trends

During the 1980s, AIDS cases alone provided an adequate picture of HIV trends because the time between infection with HIV and progression to AIDS was predictable. This predictability, however, has diminished since 1996, when highly active antiretroviral therapy (HAART) became available. Access, adherence, and response to HAART affect whether or when HIV progresses to AIDS. Thus, trends in AIDS cases alone no longer accurately reflect trends in HIV infection. AIDS trends do, however, continue to provide important information about where care and treatment resources are most needed.

Tracking HIV Trends

By April 2004, all states had adopted some system for reporting HIV diagnoses to CDC. Tracking HIV trends is challenging and depends on several factors, such as how often people are tested, when during the course of their infection they are tested, whether and how test results are reported to health departments, and how case reports (with personal identifiers removed) are shared with CDC.  Learn more about HIV infection reporting.

Read PDF icon CDC director, Dr. Julie Gerberding's "Dear Colleague" letter recommending that all states and territories adopt confidential name-based surveillance systems to report HIV infections.

A major advance has been the development of the serologic testing algorithm for recent HIV seroconversion (STARHS). STARHS is a way of analyzing HIV-positive blood samples to determine whether an HIV infection is recent or has been ongoing. In 2001, an expert panel agreed that STARHS is the best method available for measuring new HIV infections. After funding 5 areas to pilot test this method, CDC now funds 34 areas to include STARHS in their HIV incidence surveillance activities.

Monitoring HIV Risk Behavior

Behaviors are monitored with regard to risk taking, HIV testing, care seeking, and adhering to treatment for HIV in different populations.

Several federally supported surveys collect information about HIV-related behaviors of the general population. They are conducted periodically so that trends can be evaluated. A few examples are:

  • MMP (Morbidity Monitoring Project, sometimes called the Medical Monitoring Project) is a new surveillance system designed to collect information from HIV/AIDS patients who received care from randomly selected HIV care providers.
  • The NHBS (National HIV Behavioral Surveillance System), for populations at high risk, began in 2003. NHBS conducts surveys in cities with high levels of AIDS among MSM, IDUs, and heterosexuals at high risk to determine their risk behavior, testing behavior, and use of prevention services.
  • HITS (HIV Testing Survey) primarily interviewed adults who were not HIV-infected but were at high risk for HIV infection. HITS collected information about what motivates people to get tested for HIV and what behaviors place people at risk for HIV.

Monitoring HIV Counseling and Testing Behavior

The HIV Counseling and Testing System (CTS) has been used since 1989 to monitor CDC-funded HIV counseling and testing services. Through this system, each CDC-funded HIV counseling and testing episode was reported to CDC and included information about demographics, self-reported behavior, and HIV test results. Data from this system have been used to guide the development of HIV prevention programs in response to the needs of the community. Beginning in 2005, CTS will be replaced by Counseling, Testing, and Referral (CTR) system. Data parameters collected by CTR have been updated to include information on new testing technologies and client referrals to medical care and other services and to be consistent with other data collection and reporting requirements. Through cooperative agreements, CDC has funded 59 health departments and six US trust territories to provide CTR.

Understanding HIV and AIDS Data

AIDS surveillance: Through a uniform system, CDC receives reports of AIDS cases from all US states and dependent areas. Since the beginning of the epidemic, these data have been used to monitor trends. The data are statistically adjusted for reporting delays and for the redistribution of cases initially reported without risk factors. As treatment has become more available, trends in new AIDS diagnoses no longer accurately represent trends in new HIV infections; these data now represent persons who are tested late in the course of HIV infection, who have limited access to care, or in whom treatment has failed.

HIV surveillance: Monitoring trends in the HIV epidemic today requires the collection of information on HIV cases that have not progressed to AIDS. Areas with requirements for confidential name-based HIV infection reporting use the same uniform system for collecting data on HIV cases and for collecting data on AIDS cases. A total of 33 states (Alabama, Alaska, Arizona, Arkansas, Colorado, Florida, Idaho, Indiana, Iowa, Kansas, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Nebraska, Nevada, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, and Wyoming) have collected these data for at least 5 years, providing sufficient data to monitor HIV trends and to estimate risk behaviors for HIV infection.

HIV/AIDS: This term is used to refer to 3 categories of diagnoses collectively: (1) a diagnosis of HIV infection (not AIDS), (2) a diagnosis of HIV infection and a later diagnosis of AIDS, and (3) concurrent diagnoses of HIV infection and AIDS.

Last Modified: September 19, 2012
Last Reviewed: September 19, 2012
Content Source:
Divisions of HIV/AIDS Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
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