Heterosexual Anal Sex is Associated with HIV Infection in South Africa
In a recent South African study, 14% of men and 10% of women interviewed at public venues and an STI clinic reported having engaged in heterosexual anal intercourse in the past three months, and those who had done so were more likely than others to report being HIV-positive, having ever had another STI and having never used a condom (odds ratios, 1.6–2.6).1 They were also more likely to have ever exchanged money or goods for sex (1.7–1.8) and to have used alcohol or drugs in the past three months (2.0–2.8). Among respondents who had had recent anal intercourse, men reported more sex partners in the past three months than did women, and were more likely to have used condoms during vaginal or anal intercourse.
Heterosexual intercourse is believed to account for the majority of HIV infections in South Africa, and although anal intercourse carries a high risk of transmission, its prevalence and contribution to the HIV epidemic are unknown. This study examined the prevalence of heterosexual anal intercourse among men and women 18 or older; respondents were surveyed between 2003 and 2006 at a major STI clinic and 37 public venues in Cape Town. The sample included 2,593 men and 1,818 women, and more than 90% of those who were approached completed the survey. Information was collected on respondents' demographic characteristics, sexual behavior (number of partners, frequency of sex acts and condom use), HIV risk factors and HIV test results. The researchers used bivariate and logistic regression analyses to compare the responses of township and clinic respondents, and then to assess differences between those who reported having had heterosexual anal intercourse in the past three months and those who did not. Finally, the responses of men and women reporting recent heterosexual anal intercourse were compared.
Respondents' median age was 30; two-thirds were black, and a third identified themselves as colored or of mixed race. More than four in 10 were employed, and a third were married or cohabiting. Fourteen percent of men had had heterosexual anal intercourse in the past three months, as had 10% of women. Compared with other respondents, STI clinic patients had had, on average, greater numbers of sex partners (2.0 vs. 1.3) and acts of vaginal (16.5 vs. 5.2) and anal sex (1.6 vs. 0.8) in the past three months; in addition, they were more likely to have never used a condom (odds ratio, 5.0), to have ever had an STI (4.0) and to have ever received money for sex (14.3).
Respondents who had had anal intercourse in the past three months had had more sex partners during that time than had other participants (2.3 vs. 1.4), and they had used condoms during a greater proportion of vaginal sex acts (65% vs. 40%). However, they were more likely to have never used a condom (odds ratio, 1.8), to have ever had an STI (1.6) and to have ever given or received money or goods for sex (1.7–1.8); in addition, they had an increased likelihood of having used alcohol or drugs in the past three months (2.0–2.8), and were more likely to have ever been tested for HIV and to be HIV-positive (1.4 and 2.6, respectively).
Finally, among respondents who reported having had anal intercourse in the past three months, the number of unprotected episodes of anal sex was similar for men (3.1) and women (3.6). However, men reported having had more episodes of protected anal sex (6.3 vs. 3.2) and more sex partners (2.6 vs. 1.7), and they had used condoms during a greater proportion of vaginal (69% vs. 57%) and anal (64% vs. 55%) sex acts. Men also reported proportionally more anal than vaginal intercourse than did women (51% vs. 43%).
The researchers note several limitations of their study, including possible underreporting of sexual practices and risk behaviors, and their use of a convenience sample that should not be considered representative of Cape Town communities. Nonetheless, they believe that although South Africa's HIV epidemic probably cannot be attributed to unprotected anal intercourse, risk reduction interventions should address the role of anal sex in HIV transmission. The authors suggest that "counselors and health educators may require sensitivity training to increase their openness to discussing anal sex with their clients," and that intervention programs should include "condom use skills and sexual communications skills [regarding] both anal and vaginal intercourse."—J. Thomas
1. Kalichman SC et al., Heterosexual anal intercourse among community and clinical settings in Cape Town, South Africa, Sexually Transmitted Infections, 2009, 85(6):411–415.