HIV infections steady overall, rising in young gay men
by Liz Highleyman
HIV incidence in the U.S. remained stable overall during the past several years, but has risen dramatically in some population groups, researchers from the Centers for Disease Control and Prevention reported last week.
Joseph Prejean and colleagues estimated the number of new HIV infections nationwide between 2006 and 2009, based on surveillance data from 16 states and two cities (Chicago and Philadelphia). These are the first multiyear figures since the CDC's push for expanded HIV testing in 2007.
The latest estimates, described in the August 3 issue of PLoS ONE (available free online), indicate that there were 48,600 new infections among people age 13 and older in 2006 – a reduction from a previous estimate of 56,300. Overall incidence rose to 56,000 in 2007, dropped to 47,800 in 2008, and remained stable at 48,100 in 2009.
"While we're glad it's not increasing, it's not good enough," said CDC director Thomas Frieden. "The number of new infections remains too high and we need to do more to prevent it."
The stable national numbers follow a trend already evident in San Francisco, leading local public health officials to describe the city's HIV incidence as endemic rather than epidemic.
The overall national incidence figures hide some major disparities across age, race/ethnicity, geographic, and HIV transmission risk groups.
Men who have sex with men continue to bear the greatest burden of HIV. While gay and bisexual men make up approximately 2 percent of the total population, according to CDC estimates, they account for more than half of all new HIV infections – 61 percent in 2009.
About three-quarters of newly infected people in 2009 were men. African Americans (who make up 12 percent of the total population) accounted for the highest proportion of new infections, at 44 percent, followed by 32 percent for whites, 20 percent for Latinos, and 2 percent for Asians.
HIV incidence did not increase significantly, either overall or in any racial/ethnic group, during the three-year surveillance period. But it did rise by 21 percent a mong people age 13-29.
New infections increased by 34 percent among young gay and bisexual men during the study period, by 43 percent among young black men, and by 48 percent – or nearly double – among young black men who have sex with men.
Black gay men do not have more unprotected sex than other groups and tend to have fewer partners, Prejean explained during an August 3 media briefing. However, because the prevalence – or number of total cases – is higher in African American communities, there is a greater likelihood that a particular sexual partner will be HIV-positive. Other contributing factors include stigma around homosexuality, lack of access to health care, and being less likely to be tested and treated for HIV.
One bright spot in the latest data is the decrease in new infections among injection drug users, which fell from 5,300 in 2006 to 4,500 in 2009, or from 11 percent to 9 percent of all new HIV diagnoses.
"We've made tremendous progress," Frieden said. "Clearly some of it is due to the availability of clean needles, which save lives."
Test and treat
The CDC is on a mission to maximize the effectiveness of prevention funding by directing resources to the populations and areas with the greatest need – an approach dubbed "high impact prevention."
"We're overhauling how we're giving out money, making sure to give where it's needed most, for population groups that need it most, and to interventions that are most effective," said Frieden. "We must correct some of the historical anomalies; some jurisdictions will get more, some will have their resources realigned."
San Francisco may be among the cities that receive less funding as resources shift to cities with larger African American communities and heavily affected states in the southeast. Local Asian AIDS groups have already seen their funding threatened due to the relatively low number of cases in that population.
The CDC and the San Francisco Department of Public Health are shifting resources toward HIV testing and treatment, in accordance with the growing body of evidence confirming that early antiretroviral therapy dramatically reduces the risk of onward transmission.
"Unless we change what we do, we are not going to eliminate new infections, because we are in an endemic," Grant Colfax, the city's HIV Prevention Section director, recently told the Bay Area Reporter .
Frieden stressed the need for better linkage to care for people who test HIV positive, acknowledging that providing more money for AIDS Drug Assistance Programs and efforts to reduce the cost of medications will help get more people on treatment.
"We have an unprecedented opportunity to drive down infections in the U.S.," said Kevin Fenton, director of the CDC's National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention. "It's no longer about whether we can end the epidemic, but will we end the epidemic."