Back HIV/AIDS Epidemiology New U.S. HIV Infections Hold Steady Overall, but Double among Young Black Gay Men

New U.S. HIV Infections Hold Steady Overall, but Double among Young Black Gay Men

HIV incidence remained stable in the U.S. at around 50,000 new cases between 2006 and 2009, according to a report in the August 3, 2011, online edition of PLoS ONE. But the overall numbers hide some major disparities. People of color and men who have sex with men continue to be most heavily impacted, with incidence among young black gay men rising by nearly 50%.alt

Over the course of the epidemic, U.S. public health officials have employed different methods for estimating the number of people newly infected and living with HIV. In the early years, concerns about stigma and criminalization, as well as lack of effective treatment, led to provisions for anonymous reporting and limited emphasis on testing.

More recently the Centers for Disease Control and Prevention (CDC) has pushed for routine testing and mandated name-based reporting, which has enabled more accurate estimates of the number of new and existing cases. Today, with a growing body of evidence showing that early antiretroviral therapy (ART) both has health benefits for HIV positive people and can dramatically reduce the likelihood of transmission, a push is on for more widespread testing and better linkage to treatment and care.

As described in the new report, Joseph Prejeanfrom the CDC's Division of HIV/AIDS Preventionand colleagues looked at HIV incidence, or new infections, using surveillance data from 16 states and 2 cities (Chicago and Philadelphia) that receive funding to collect this information. As Prejean explained in a media briefing on August 3, those figures were then extrapolated to other states to give a national estimate.

The CDC previously estimated U.S. HIV incidence in 2006 to be 56,300 new cases. The current analysis updated the 2006 estimate and calculated incidence for 2007-2009 using improved methodology -- the first multiyear estimate using the new approach.

Results

  • The estimate for overall HIV incidence among people age 13 and older in 2006 was reduced to 48,600 from the previous estimate of 56,300.
  • The estimated overall incidence for 2007 was 56,000 (similar to the old 2006 number).
  • Estimated incidence fell to 47,800 in 2008 and remained roughly stable at 48,100 in 2009.
  • From 2006 to 2009 HIV incidence did not change significantly, either overall or for specific race/ethnicity or transmission risk groups.
  • These numbers, however, mask some wide disparities among smaller sub-populations.
  • The greatest increases were seem among men who have sex with men (MSM), young people, and African-Americans, with the biggest jump for people falling into all 3 groups.
  • Among all people age 13-29 years (the youngest age group studied), incidence increased by 21% from 2006 to 2009.
  • Among young gay/bisexual/MSM, the increase was 34% during this period.
  • Among all young black/African-American men, the new infection rate rose by 43%.
  • Among young black MSM, the increase reached 48% -- almost doubling incidence over 4 years -- reflecting an estimated 12% annual percentage increase.
  • In 2009, HIV transmission route proportions were as follows:
    • Gay/bisexual/MSM: 61% of new infections;
    • Heterosexual contact: 27%;
    • Injection drug use: 9%;
    • MSM who also injected drugs: 3%.
  • While gay/bisexual/MSM make up approximately 2% of the total U.S. population (according to CDC estimates), they accounted for more than half of all new HIV infections: 56% in 2006, 58% in 2007, 56% in 2008, and 61% in 2009.
  • While blacks/African-Americans represent 14% of the total population, they accounted for 44% of new HIV infections in 2009, and had an infection rate nearly 8 times that of whites.
  • Hispanics/Latinos made up 16% of the population and accounted for 20% of new HIV infections in 2009, with a rate nearly 3 times that of whites.
  • Nevertheless, given the larger share of whites in the total population, white MSM accounted for the highest number of new HIV infections during all 4 years.

These findings led the researchers to conclude that while overall HIV incidence in the U.S. was relatively stable during 2006-2009, among young MSM -- particularly black/African-American MSM -- incidence increased.

"HIV continues to be a major public health burden, disproportionately affecting several populations in the United States, especially MSM and racial and ethnic minorities," they wrote. "Expanded, improved, and targeted prevention is necessary to reduce HIV incidence."

The reasons for this dramatic increase among young black MSM are not clear, Frieden explained during the media briefing, given that prior studies have found that black gay men do not have more unprotected sex and tend to be less likely to inject drugs. But the prevalence, or number of total HIV cases, is substantially higher in African-American communities, meaning there is a higher likelihood that any particular sexual partner will be HIV positive.

Other possible factors, he said, include stigma surrounding homosexuality, poverty, lack of access to healthcare, a higher rate of other sexually transmitted diseases (which can facilitate HIV transmission and acquisition), and a greater likelihood of not being tested, not knowing one's status, and therefore not being on treatment.

"The rate of HIV infection remains one of the most glaring health disparities in the United States," the CDC said in a statement summarizing the findings. "The National HIV/AIDS Strategy, announced in July 2010, calls for increased efforts to reduce HIV incidence among gay and bisexual men, transgender individuals, injection drug users, and among racial and ethnic groups with a disproportionate burden of HIV disease. These efforts, which are being implemented by CDC, other governmental agencies, state and local health departments, and many partners throughout the country, will be vital for the United States to break through the persistent patterns of HIV in this country."

To this end, the CDC is working to maximize the effect of prevention dollars by directing resources to the populations and geographical areas with the greatest need -- an approach dubbed "high impact prevention." But this has raised concerns among other groups that are likely to lose some of their funding in an effort to better reflect shifts in the epidemic. "We must correct some of the historical anomalies [in resource distribution]," Frieden said. "Some jurisdictions will get more, some will have their resources realigned."

"It's not enough to promote testing, we have to promote linkage to care. And it's not enough to promote linkage to care, we have to promote continuity of care," Frieden continued. "[We must] focus on programs that work, in the places that need it most, for the people who need it most" and "on an appropriate scale to have an impact."

8/5/11

Reference

J Prejean, R Song, A Hernandez, et al. Estimated HIV Incidence in the United States, 2006–2009. PLoS ONE 6(8): e17502 (free full text). August 3, 2011.

Other Source

U.S. Centers for Disease Control and Prevention. CDC Statement on new estimates. August 3, 2011.