Four in 10 US women enrolled in a study of HIV infection risk had concurrent partners, and the usual gap between partners was only 1 month.
Preventing HIV transmission among women in the United States and countries with similar HIV epidemics depends on better understanding of their risk behaviors and patterns. HPTN 064 aimed to study these variables and HIV incidence in women living in 10 US communities.
Also called The Women’s HIV Seroincidence Study (ISIS), HPTN 064 ran from April 2009 to March 2011 and involved 18- to 44-year-old women willing to be tested for HIV. This analysis included 2099 women who answered a baseline survey about sexual concurrency. Women reported whether they had concurrent partners, whether they believed partners had concurrent partners, whether partners had been tested for HIV, and how often women had sex in the past 6 months.
While 40% of women reported having concurrent partners, 36% said their partners had concurrent partners. Almost one quarter of these women (24%) had both concurrent partnerships and partners with concurrent partners.
Among women who had more than 1 recent partner but no concurrent partners, the median gap between sex partners was 1 month.
Reported multiple episodes of unprotected vaginal intercourse with 2 or more recent partners were most frequent among women with concurrent partners and partners who had concurrent partners (60%), followed by women who had concurrent partners but whose partners did not (50%), women who did not have concurrent partners but whose partners did (33%), and women without concurrent partners or partners with concurrent partners (14%) (P < 0.0001).
Only 17% of women with no concurrent partners and with partners who had no concurrent partners did not know whether recent partners had an HIV test. Lack of awareness of recent partner HIV testing was significantly higher among women who had concurrent partners themselves (41%), women whose partners had concurrent partners (40%), and women who had concurrent partners themselves and whose partners had concurrent partners (48%) (P < 0.0001).
The HPTN 064 investigators propose that “these network patterns and short gaps between partnerships may create substantial opportunities for HIV transmission in this sample of women at high risk for HIV infection.”