The HIV Prevention Trials Network (HPTN), a worldwide collaborative clinical trials network that develops and tests the safety and efficacy of primarily non-vaccine interventions designed to prevent the acquisition and transmission of HIV,  announced the results from its HPTN 064 Women's HIV Seroincidence Study (ISIS) which shows that the HIV incidence rate for US women living in areas hardest hit by the epidemic is much higher than the overall estimated incidence rate in the US for black adolescent and adult women.

An HIV incidence of 0.24% in the study cohort of 2,099 women (88% black), a rate that is five fold higher than that estimated for black women overall by the Centers for Disease Control and Prevention (CDC). The rate noted in the HPTN 064 (ISIS) study is comparable to estimated HIV incidence rates in the general population in several countries in sub-Saharan Africa including the Congo (0.28%) and Kenya (0.53%), underscoring the substantial ongoing HIV transmission within specific US populations, including women at risk as defined in this study. The incidence rate observed in HPTN 064 is based on findings from women enrolled from six geographical areas in the US where HIV and poverty are known to be more common.

Study Chair Sally Hodder, M.D., with the University of Medicine and Dentistry of New Jersey-New Jersey Medical School commenting on the findings said, "We have known that black women in the US are disproportionately impacted by HIV, however, the magnitude of this disparity in areas hardest hit by the HIV epidemic underscores the gravity of the problem."

Women constitute roughly one-quarter of new HIV infections in the US with 66 per cent of these infections occurring among black women, although black women constitute only 14 per cent of the US female population. In the US, the age-adjusted death rate of black women with HIV is roughly 15 times higher than that observed for HIV-infected white women.

"Despite prevention efforts in the last 30 years, the reality is that we still have ongoing HIV transmission in the US that requires focusing prevention efforts," said Hodder.

The HPTN 064 (ISIS) study, funded by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health, enrolled a total of 2,099 women, ages 18 to 44 years, between May 2009 and July 2010. Eighty-eight percent of women were black, 12% Hispanic/Latina. Women were enrolled from 10 communities in six distinct geographical areas in the northeast and southeast regions of the US; Atlanta, GA, Raleigh-Durham, NC, Washington D.C., Baltimore, MD, Newark, NJ, New York City, NY.

The study used a novel approach to recruit participants, focusing on geographic areas of the US with the highest HIV prevalence rates in women, i.e. "hot spots." Women without a prior positive HIV test living in areas with high HIV prevalence and poverty were eligible for enrollment and were interviewed about many key aspects of their lives including mental health, sexual behavior, history of sexually transmitted infections (STIs), domestic violence, social support, financial insecurity and health care utilization.  

Another significant finding from the study is the high number of women who were found to have HIV infection at the time of enrollment (32 women or 1.5%). These women were previously unaware of their HIV status. This finding highlights the need to increase awareness of HIV risk and expand novel HIV testing and prevention efforts in high prevalence areas of the US.
"The study provides convincing evidence that more effort is needed to develop effective prevention strategies for high risk populations in order to stem the HIV epidemic in the US," said Sten Vermund from Vanderbilt University, Principal Investigator of the HPTN.