Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women

Context Herpes simplex virus type 2 (HSV-2) is one of the most common sexua lly transmitted infections in the United States. No prospective study has s hown the ability of condoms to reduce transmission of HSV-2. Objective To evaluate risk factors for HSV-2 acquisition and efficacy of co ndoms in prevention of HSV-2 transmission. Design Analysis of data from a randomized, double-blind, placebo-controlled trial conducted December 13, 1993, to June 28, 1996, of an ineffective can didate HSV-2 vaccine with 18 months of follow-up. Setting Eighteen clinical trial centers in the United States. Participants A total of 528 monogamous couples discordant for HSV-2 infecti on, including an HSV-2- susceptible population of 261 men and 267 women. Main Outcome Measure Acquisition of HSV-2 infection by susceptible partners , compared with those remaining free of HSV-2 with regard to demographic ch aracteristics, sexual activity, and condom use. Results Twenty-six women (9.7%) vs 5 men (1.9%) acquired HSV-2, for a rate per 10000 sex acts (episodes of sexual intercourse) of 8.9 vs 1.5, respecti vely (P<.001). In multivariable analysis, younger age (adjusted hazard rati o [HR] per 5 years, 1.57; 95% confidence interval [Cl], 1.22-2.04), seropos itivity for HSV-1 and HSV-2 vs HSV-2 alone in the source partner (adjusted HR, 2.34; 95% Cl, 1.14-4.82), and more frequent sexual activity (adjusted H R per additional sex act per week, 1.10; 95% Cl, 1.01-1.19) were associated with higher risk of HSV-2 acquisition. Condom use during more than 25% of sex acts was associated with protection against HSV-2 acquisition for women (adjusted HR, 0.085; 95% Cl, 0.01-0.67) but not for men (adjusted HR, 2.02 ; 95% Cl, 0.32-12.50). Risk of HSV-2 transmission declined from 8.5 per 100 person-years in the initial 150-day interval to 0.9 per 100 person-years i n the final 150-day interval (P=.002 for trend), concurrent with a decrease in sexual activity and proportion of sex acts occurring when the source pa rtner had genital lesions. Conclusions Condom use offers significant protection against HSV-2 infectio n in susceptible women. Changes in sexual behavior, correlated with counsel ing about avoiding sex when a partner has lesions, were associated with red uction in HSV-2 acquisition over time. These data suggest that identificati on of discordant couples can reduce transmission of HSV-2, especially for h eterosexual couples in which the male partner has HSV-2 infection.