Herpes Simplex Virus Type 2 Infection as a Risk Factor for Human Immunodeficiency Virus Acquisition in Men Who Have Sex With Men

The authors conducted a nested case-control study to examine the association between HSV-2 seropositivity and subsequent risk of HIV acquisition among men who have sex with men, with the goal of determining whether HSV-2 treatment could serve as an HIV prevention target in this population.

The researchers performed a case-control study nested within two multisite cohort studies: the CDC Collaborative HIV Seroincidence Study in San Francisco, Denver and Chicago (1993-1994) and the National Institute of Allergy and Infectious Diseases HIV Vaccine Preparedness Study in San Francisco, Denver, Chicago, Boston, Seattle and New York (1995-1997). HIV seronegative MSM were eligible if they had engaged in anal sex within the past year; subjects were followed for 18 months at six-month intervals and completed semistructured interviews including questions about risk behaviors and STD symptoms.

For the current study, the authors defined case subjects as men who were HIV seronegative at baseline and seroconverted to HIV-positive during the study. Control subjects were chosen from the men who remained HIV seronegative throughout the study. The project studied 116 case subjects and 342 control subjects.

The study found that case subjects who acquired HIV during the study period were more likely than control subjects to be members of a racial or ethnic minority, less likely to have health insurance coverage, and more likely to report injection drug use. For the 12-month period before seroconversion, case subjects reported a higher number of sexual partners than control subjects (median 6.5 vs. 4.5 partners) and a higher frequency of unprotected receptive anal sex (median 3 vs. 1.5 episodes) and any condom breakage (39 percent vs. 29 percent). Forty-six percent of cases were HSV-2 seropositive before HIV seroconversion, compared with 34 percent of control subjects before their last visits. Overall, investigators found, 6 percent of cases and 11.4 percent of controls reported herpes symptoms in the previous 12 months.

"In a multivariable logistic regression analysis assessing the association of HIV seroconversion with prior HSV-2 infection," the investigators wrote, "we found prior HSV-2 seropositivity to be associated with a 1.8-fold increased risk of HIV seroconversion. Having >12 (compared with <3) sex partners in the previous year, lack of reported herpes outbreaks in the past 12 months, and lack of health insurance were also independently associated with HIV acquisition. Although men who reported having herpes symptoms within the past 12 months had a higher median number of sexual partners than men who did not report such symptoms (9 vs. 4.5), no significant differences in the proportion reporting any unprotected receptive or insertive anal intercourse were observed. Self-reported bacterial STDs within the past 12 months did not appear to increase the risk of HIV seroconversion. The association of HSV-2 seropositivity with HIV acquisition did not change when the 16 MSM who reported injection drug use in the previous year were included. No interactions between HSV-2 infection and clinical, demographic and behavioral variables were found."

"HSV-2 increases the risk of HIV acquisition, independent of recognized herpes lesions and behaviors reflecting potential HIV exposure," Renzi and colleagues concluded. "HSV-2 suppression with antiviral therapy should be evaluated as an HIV prevention strategy among MSM."

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