National Overview

The Centers for Disease Control and Prevention estimates that at the end of 2006, 1.1 million adults and adolescents were living with HIV infection in the US. HIV continues to be a leading cause of death. In 2005, HIV was the fifth leading cause of death among people aged 35-44. The impact is greater on Blacks and Hispanics. For instance, HIV was the third leading cause of death for Blacks aged 35-44, the fourth leading cause for Hispanics 35-44 and the fifth leading cause of death for Whites 25-44.

In the 33 states with confidential name-based HIV infection reporting, more than 35,000 people were newly diagnosed with HIV in 2006 alone. Among the new diagnoses, 74% were male and 26% female. Male-to-male sexual contact continues to be the leading mode of transmission, accounting for 49% of all recent HIV/AIDS diagnoses and 67% of male diagnoses. Blacks, who make up approximately 12% of the US population, accounted for 49% of new HIV diagnoses in 2006. Whites accounted for 30% and Hispanics for 18% of new diagnoses.

Chicago Overview

There are more than 22,000 people living with HIV/AIDS in Chicago; over half of which are living with HIV and have not progressed to AIDS. The number of people living with HIV/AIDS continues to grow as new HIV and AIDS cases are diagnosed every year and less people die as a result of HIV. Since 2001, over 1,000 new HIV (not AIDS) diagnoses are made each year, surpassing the number of AIDS diagnoses.

Despite declines in HIV-related mortality, HIV continues to be in the top ten leading causes of death, ranking fourth among people between the ages of 34-55 who died in Chicago.

Recently diagnosed HIV infections show that males and people of color are heavily impacted by HIV. Of the 1,551 diagnosed HIV infections made in 2006, 80% were males and 20% were females. Close to three out of every four HIV infection diagnoses were among Blacks and Hispanics.

While the overall number of infections has declined by close to 20% in the last six years (from 1,997 in 2000 to 1,551 in 2006), not all demographic and risk groups have experienced the same trend. For instance, adolescent and young adults (15-24), who accounted for 16% of newly diagnosed HIV infections in 2006, experienced a 42% increase in the number of HIV infections between 2000 and 2006. In contrast, 35-44 year olds, who account for 83% of HIV infections, experienced a 34% decline in the number of diagnosed HIV infections during the same time period (see Figure 1).

Similar to national trends, male-to-male sexual contact continues to be the leading mode of transmission, accounting for the largest percentage of HIV infections and AIDS diagnoses. In 2000, men who have sex with men (MSM) accounted for 46% of HIV infections and by 2006 accounted for 63% of infections. The number of HIV infections resulting from injection drug use (IDU) has decreased by more than 60%, from 526 in 2000 to 201 in 2006. With the decline in cases resulting from IDU, heterosexual contact has emerged as the second leading mode of HIV transmission in Chicago, accounting for 21% of HIV infections in 2006.

Race/Ethnicity

Blacks are disproportionately affected by HIV. They represent only 36% of Chicago’s population yet account for 55% of recently diagnosed HIV infections. Of the 22,650 people living with HIV/ AIDS, 54% are Black, 27% are White, 16% are Hispanic and 3% are of another race. The 2006 HIV infection rate in Blacks is nearly twice the rate of Whites (92 out of every 100,000 Blacks compared to 48 per 100,000 Whites and 31 per 100,000 Hispanics). Among males, Black males accounted for the largest number of diagnosed HIV infections and have the highest HIV infection rate of any race/ ethnicity group (144 per 100,000, compared to 94 per 100,000 for White males and 50 for per 100,000 Hispanic males).

Nearly 30% of people diagnosed with HIV infection in 2006 progressed to AIDS within a year. A slightly larger percentage of Hispanics (36%) and Blacks (32%) progressed from HIV to AIDS in a year than Whites (23%). Males represent the largest percentage of HIV infections for all race/ethnicity groups but the percentages vary widely. In 2006, males accounted for 95% of HIV infections among Whites, 83% among Hispanics, and 71% among Blacks. Blacks represent nearly three-quarters of all adolescent and young adults diagnosed with HIV infection in 2006; Whites accounted for 13% and Hispanics for 12% of infections.

Men Who Have Sex with Men (MSM)

There are 12,821 men who have sex with men (MSM) living with HIV/AIDS in the city of Chicago. Of these, 5,174 (40%) are White, 5,048 (39%) are Black, 2,185 (17%) are Hispanic, and 414 (3%) are of another race.

Men are infected with HIV primarily through male-to-male sexual contact. Among male HIV infections diagnosed in 2006, 79% were transmitted through male-to-male sexual (MSM) contact. This pattern holds for all race/ethnicity groups, but the proportion differs considerably across groups. MSM accounted for 91% of White, 83% of Hispanic, and 70% of Black male HIV infections.

Black MSM account for 28% of all 2006 diagnosed HIV infections, White MSM account for 22% and Hispanic MSM for 11% of infections. Black MSM are significantly younger than White and Hispanic MSM at time of diagnosis. Fifty-seven percent (57%) of Black MSM diagnosed with HIV infection in 2006 were under the age of 35, compared to 53% of Hispanic and 39% of White MSM diagnoses.

Women and Children

There are 4,866 females living with HIV/AIDS in the City of Chicago. Of these, 3,701 (76%) are Black, 617 (13%) are Hispanic, 439 (9%) are White and 109 (2%) are of another race.

In 2006, women accounted for 20% of diagnosed HIV infections, a percentage that has remained relatively stable over the last six years. The gender gap, however, varies considerably by race/ ethnicity. Women represent 29% of all HIV infections among Blacks, 17% among Hispanics, and 5% among Whites.

The leading mode of transmission for women is heterosexual contact. Among female HIV infections diagnosed in 2006, 79% were transmitted through heterosexual contact, and 20% as a result of injection drug use.

In 2006, 248 Black females were diagnosed with HIV infection. Black females are heavily impacted by the epidemic. They represent 37% of Chicago’s female population yet account for the overwhelming majority (79%) of female HIV infections (see Figure 2). The HIV infection rate in Black females is 49 per 100,000, more than 10 times the rate in White women and 4 times greater than the rate in Hispanic women.

There are 131 children under 15 years of age living with HIV or AIDS in the City of Chicago, representing a rate of 13 per 100,000 children in this age group. Of children under the age of 15 at time of HIV diagnosis, 81% acquired HIV perinatally. The number of HIV/AIDS diagnoses resulting from perinatal transmission peaked in 1993 when 38 cases were diagnosed and has declined markedly since then, averaging less than 5 cases each year.

• HIV/AIDS in Chicago, General Epidemiology