
HIV incidence is the estimated total number of new (total number of diagnosed and undiagnosed) HIV infections in a given period. In recent years, CDC has used new technology and methodology to more directly measure the number of new HIV infections in the United States. HIV incidence estimates are used to monitor the HIV epidemic in this country, and to guide policies and programs created to serve communities and populations most affected by HIV. HIV incidence reflects the leading edge of HIV transmission, HIV infection trends, and the impact of HIV prevention efforts.
Overall
Comparing 2008 to 2010, the overall estimated number of HIV infections remained stable in every age group and in all racial/ethnic groups. There were decreases among women; including African American women. However burden is still high among African Americans and men who have sex with men (MSM). There were sharp increases in youth, especially young African American MSM.

Age at Infection
In 2010, the estimated number of new HIV infections was highest among individuals aged 25-34 (31%, 14,500 [95% CI: 12,500-16,400]), followed by individuals aged 13-24 (26%, 12,200 [95% CI: 10,500-13,800]).
Transmission Category
Comparing 2008 to 2010, the estimated number of new HIV infections among MSM increased 12%, from 26,700 (95% CI: 23,400-30,000) in 2008 to 29,800 (95% CI: 26,200-33,500) in 2010. The number of new HIV infections among females with infection attributed to heterosexual contact decreased 18% from 9,800 (95% CI: 8,200-11,400) in 2008 to 8,000 (95% CI: 6,700-9,200) in 2010. In 2010, the majority of new HIV infections was attributed to male-to-male sexual contact (63% overall and 78% among males). Among females, the largest percentage of new HIV infections was attributed to heterosexual contact (84%).
Sex
Among females, the estimated number of new HIV infection decreased 21%, from 12,000 (95% CI: 10,100-13,900) in 2008 to 9,500 (95% CI: 8,100-10,900) in 2010. In 2010, the rate of new HIV infections among males (30.7) was 4.2 times that of females (7.3).
Blacks/African Americans
Blacks/African Americans continue to be disproportionately affected by HIV infection. The estimated rate of new HIV infections among blacks/African Americans (68.9) was 7.9 times as high as the rate in whites (8.7). In 2010, of all of the new HIV infections among blacks/African Americans, 51% were among MSM and 38% were attributed to heterosexual contact.
Though the estimated number of new HIV infections among black/African American females decreased, they are still disproportionately affected by HIV infection. In 2010, 87% of black/African American females newly infected with HIV had infections attributed to heterosexual contact.
Comparing 2008 to 2010, the number of new HIV infections among black/African American males was stable at 14,400 (95% CI: 12,400-16,400) in 2008 and 14,700 (95% CI: 12,600-16,900) in 2010. By age at infection, the largest percentage (38%) of new HIV infections among black/African American males in 2010 occurred in those aged 13-24 years; this percentage was higher than the percentage for the same group of Hispanic/Latino males (25%) and of white males (16%).
Hispanics/Latinos
Hispanic/Latinos continue to be disproportionately affected by HIV infection. In 2010, Hispanics/Latinos comprised 21% of the new HIV infections. The rate of new HIV infections for Hispanics/Latinos (27.5) was three times the rate for whites (8.7). In 2010, of all new HIV infections among Hispanics/Latinos, 68% were among MSM and 20% were attributed to heterosexual contact.
Comparing 2008 to 2010, the number of new HIV infections among Hispanic/Latina females remained stable overall at 1,600 (95% CI: 1,200-2,100) in 2008 and 1,400 (95% CI: 980-1,800) in 2010, and was stable in all age and transmission groups. The rate of new HIV infections for Hispanic/Latina females (8.0) was 4.2 times that for white females (1.9).
Comparing 2008 to 2010, the number of new HIV infections among Hispanic/Latino males remained stable at 7,500 (95% CI: 6,200-8,700) in 2008 and 8,500 (95% CI: 7,000-9,900) in 2010, and was stable in all age and transmission category groups. In 2010, Hispanics/Latinos males comprised 87% of the new HIV infections among all Hispanics/Latinos and the majority of new HIV infections (79%) among Hispanic/Latino males were attributed to male-to-male sexual contact.
Men Who Have Sex With Men
Among MSM, the estimated number of new HIV infections increased overall and among MSM aged 13-24. MSM remain the population most heavily affected by HIV infection. Comparing 2008 to 2010, the number of new HIV infections among MSM increased 12% from 26,700 (95% CI: 23,400-30,000) in 2008 to 29,800 (95% CI: 26,200-33,500) in 2010, with a 22% increase among MSM aged 13-24 from 7,200 (95% CI: 6,100-8,300) in 2008 to 8,800 (95% CI: 7,500-10,100) in 2010. Although MSM represent about 7% of the male population in the United States, in 2010 MSM accounted for 78% of the new HIV infections among males.
CDC published new incidence estimates in December 2012 in the CDC HIV Surveillance Supplemental Report series. These estimates use the Stratified Extrapolation Approach to extrapolate (to the rest of the United States) from areas contributing national data for HIV incidence estimates. For 2007-2010, this includes 18 states and 2 cities which comprised 24 of the 25 areas funded for HIV incidence surveillance. The Stratified Extrapolation Approach applies the ratio of the estimated incidence of HIV infection to the estimated number of diagnoses of HIV infection in a given year within the areas that did contribute data for incidence estimation to the estimated number of diagnoses of HIV infection in the areas that did not contribute data.
Resources for HIV Incidence
- Fact Sheet: Estimates of New HIV Infections in the United States, 2007-2010
- Fact Sheet: HIV in the United States: At a Glance
- Fact Sheet: Healthy People 2020 Leading Health Indicators Objective HIV-13: Proportion of Persons Living With HIV Who Know Their Serostatus
- Centers for Disease Control and Prevention. Estimated HIV Incidence in the United States, 2007-2010. HIV Surveillance Supplemental Report 2012;17(No.4). Published December 2012.
- Surveillance Brief: Surveillance Systems Supported by the Division of HIV/AIDS Prevention
- Surveillance Brief: Terms, Definitions, and Calculations Used in CDC HIV Surveillance Publications
- Consultation Summary: Consultation on Advancing HIV Incidence Surveillance Summary