Rate of HIV Stable, but MSM See High Rates of Infection

By Eric Brus

Late last month, the Centers for Disease Control and Prevention (CDC) released their new surveillance report, Diagnoses of HIV infection in the United States and Dependent Areas, 2013. CDC estimates that there were about 47,352 newly diagnosed cases of HIV infection during 2013 in the 50 states, the District of Columbia, and six U.S. dependent areas. The estimated number of new HIV diagnoses has remained relatively stable during the five-year period from 2009 through 2013, according to CDC.

Although gay, bisexual, and other men who have sex with men (MSM) represent an estimated 2% of the U.S. population, according to CDC, over two-thirds (68%) of all HIV diagnoses in 2013 were among MSM. Blacks/African Americans represent 12% of the U.S. population but accounted for 46% of HIV diagnoses. Persons of Hispanic/Latino ethnicity represent 17% of the U.S. population but accounted for 21% of HIV diagnoses.

In considering this surveillance data, it is important to note that the number of new diagnoses of HIV is not the same as HIV incidence - the number of newly occurring infections. The reason is that many HIV-infected persons do not become aware of their HIV status until many months or years after they are infected. In fact, CDC estimates that about one in seven Americans living with HIV do not know their HIV status. The 2013 surveillance data include people who were diagnosed with HIV or AIDS during that year, whether they were infected recently or long ago.

In 2013, the estimated rate of diagnoses of HIV infection was 15 per 100,000 population -- a rate similar to those seen in the previous four years. However, despite the stability in overall diagnosis rates, there were some notable differences in the rates seen within specific demographic groups.

Age: More than half (56.8%) of all estimated HIV diagnoses occurred among persons in their twenties (33.5%) or thirties (23.3%). About one-fifth (20.4%) occurred among persons in their forties. More than one-sixth (18.1%) of the estimated diagnoses occurred among people 50 or older. The remaining 4% of diagnoses occurred among persons under 20, with the vast majority of those in the 15-to-19 age group.

During the period from 2009 through 2013, the rates of HIV diagnoses increased among persons aged 13-14, 20-29, and 60 or older; the diagnosis rates decreased among persons aged 15-19 and 35-44; and the diagnosis rates remained fairly stable for all other groups. During 2013, young people 20-24 years old accounted for the highest percentage of new HIV diagnoses (17.0%), while those in the 25-29 age range had the highest HIV diagnosis rate -- 36.3 per 100,000 -- more than twice the national average.

Race/Ethnicity: Blacks/African Americans accounted for nearly half (46.1%) of all estimated newly reported HIV cases in 2013, with Whites accounting for 27.7%, Hispanics/Latinos accounting for 21.4%, and all other racial/ethnic groups accounting for about 5%. The HIV diagnosis rates per 100,000 continued to be substantially higher for Blacks/African Americans (55.9), Hispanics/Latinos (18.7), Native Hawaiian/Pacific Islanders (12.7), and persons of multiple races (16.8) compared to Whites (6.6). Put another way, compared to Whites, HIV diagnosis rates were 8.5 times higher among Blacks/African Americans, 2.8 times higher among Hispanics/Latinos, 1.9 times higher among Native Hawaiian/Pacific Islanders, and 2.5 times higher among persons of multiple races.

Gender: In 2013, four-fifths (80.3%) of the estimated new HIV diagnoses among adults and adolescents occurred in males, with the remaining 19.7% in females. Infection rates per 100,000 population decreased between 2009 and 2013 for adult and adolescent females, but remained fairly stable for males.

Transmission Category:
Male-to-male sexual contact accounted for 64.8% of U.S. estimated new HIV cases in 2011, and an additional 2.7% were attributed to male-to-male sexual contact plus injection drug use. This means that over two-thirds of new diagnoses for the year were among gay, bisexual, and other men who have sex with men (MSM). The percentage of diagnoses in other major risk transmission categories were as follows: high-risk heterosexual contact, 25.1%; injection drug use (IDU), 6.5%; and perinatal exposure, 0.2%. The number of females in the high-risk heterosexual transmission category is more than twice that of the number of males in this category.

Considering transmission category and gender together reveals that 86.6% of all adult and adolescent female cases are associated with high-risk heterosexual exposure, while 84.3% of all male adult and adolescent cases were associated with male-to-male sexual contact (including MSM plus IDU).