Unless otherwise noted, the following data are from the CDC HIV Surveillance Report: Diagnoses of HIV infection and AIDS in the United States and Dependent Areas, 2009.
Table of Contents
Diagnosis of HIV infection: This refers to persons diagnosed with HIV infection, regardless of the stage of disease at diagnosis (e.g., if they have progressed to AIDS) from the 45 areas (40 states and 5 U.S. dependent areas) that have had confidential name-based HIV infection reporting long enough (i.e., since at least January 2006) to allow for stabilization of data collection and for adjustment of the data in order to monitor trends. According to the cumulative estimated number of AIDS diagnoses through 2009, these 40 states represent approximately 75% of AIDS diagnoses in the 50 states and the District of Columbia.
AIDS Diagnosis: This refers to persons diagnosed with Stage 3 HIV infection (AIDS), based on the 2009 CDC case definition for adults, adolescents and children.
Dependent Areas: American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands.
40 States and 5 U.S. Dependent Areas with Confidential Name-Based HIV Infection Reporting: Alabama, Alaska, Arizona, Arkansas, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Michigan, Minnesota, Mississippi, Missouri, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, Wyoming, American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands. Learn more about HIV infection reporting.
Transmission Category: The classification of a case that indicates the risk factor most likely to have been responsible for transmission. Cases are counted only once in a hierarchy of transmission categories. Persons with more than 1 reported risk factor for HIV infection are classified in the transmission category listed first in the hierarchy. The exception is men who report sexual contact with other men and injection drug use; this group makes up a separate transmission category.
HIV Incidence: The number of new HIV infections in a specific population during a specific period of time.
HIV Prevalence: The number of people living with HIV infection in a given year.
For more definitions and details about how HIV infection and AIDS data are tabulated, read the "Technical Notes" from the HIV Surveillance Report: Diagnoses of HIV Infection and AIDS in the United States and Dependent Areas, 2009.
For additional details on HIV disease surveillance, view the Kaiser Family Foundation tutorial: Understanding HIV/AIDS Surveillance Data in the United States.
HIV Prevalence Estimate
Prevalence is the number of people living with HIV infection at the end of a given year.
At the end of 2006, an estimated 1,106,400 persons (95% confidence interval 1,056,400-1,156,400) in the United States were living with HIV infection, with 21% undiagnosed.1
For more information see "HIV in the United States."
- CDC. HIV Prevalence Estimates -- United States, 2006. MMWR 2009;57(39):1073-76.
HIV Incidence Estimate
Incidence is the number of new HIV infections that occur during a given year.
In 2008, CDC estimated that approximately 56,300 people were newly infected with HIV in 20061 (the most recent year that data are available). Over half (53%) of these new infections occurred in gay and bisexual men. Black/African American men and women were also strongly affected and were estimated to have an incidence rate than was 7 times as high as the incidence rate among whites. Visit the HIV incidence page for more details.
- Hall HI, Ruiguang S, Rhodes P, et al. Estimation of HIV incidence in the United States. JAMA. 2009;300:520-529.