HIV Transmission among Men Who Have Sex with Men Due to Condom Failure

Despite preventive efforts, HIV incidence remains high among men who have sex with men (MSM) in industrialized countries. Condoms are an important element in prevention but, given the high frequency of condom use and their imperfect effectiveness, a substantial number and proportion of HIV transmissions may occur despite condoms. We developed a model to examine this hypothesis.

We used estimates of annual prevalent and incident HIV infections for MSM in Ontario. For HIV-negative men, we applied frequencies of sexual episodes and per-contact HIV transmission risks of receptive and insertive anal sex with and without a condom and oral sex without a condom. We factored in the proportion of HIV-infected partners receiving antiretroviral therapy and its impact in reducing transmissibility. We used Monte-Carlo simulation to determine the plausible range for the proportion of HIV transmissions for each sexual practice.

Among Ontario MSM in 2009, an estimated 92,963 HIV-negative men had 1,184,343 episodes of anal sex with a condom and 117,133 anal sex acts without a condom with an HIV-positive partner. Of the 693 new HIV infections, 51% were through anal sex with a condom, 33% anal sex without a condom and 16% oral sex. For anal sex with a condom, the 95% confidence limits were 17% and 77%.

The proportion of HIV infections related to condom failure appears substantial and higher than previously thought. That 51% of transmissions occur despite condom use may be conservative (i.e. low) since we used a relatively high estimate (87.1%) for condom effectiveness. If condom effectiveness were closer to 70%, a value estimated from a recent CDC study, the number and proportion of HIV transmissions occurring despite condom use would be much higher. Therefore, while condom use should continue to be promoted and enhanced, this alone is unlikely to stem the tide of HIV infection among MSM.

Below: Modeled distribution of fraction of new infections due to each sexual practice, with mean and 95 percent confidence intervals

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By: Remis RS1, Alary M2, Liu J1, Kaul R3, Palmer RW1.

• 1Ontario HIV Epidemiologic Monitoring Unit, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada.
• 2Centre de Recherche, CHU de Québec, Québec, Canada; Département de Médecine Sociale et Préventive, Faculté de médecine, Université Laval, Québec, Canada; Institut National de Santé Publique du Québec, Québec, Canada.
• 3Department of Medicine, University Health Network, University of Toronto, Toronto, Canada.  

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Condoms Used But Sex Not Well Protected - Female Sex Workers in China

Condom use is often equated to safer sex. The prevalence of condom use during sex work among female sex workers (FSW) in China is high. Condom use, however, co-exists with condom failure and improper use and hence risk of HIV transmission. In a cross-sectional study, we interviewed 195 FSW in Shenzhen, China. 

The prevalence of condom use in the last episode of sex work was 97.4%, However, respectively 53.8 and 86.2% had experienced at least one condition of condom failure that may lead to genital contact (wearing condoms after penetration, condom breakage/slippage, condoms removed by clients) and at least one condition of improper condom use (not removing air from the tip of the condom, not pulling it down to the root of penis and not choosing good quality condoms). 

Factors of individual level (e.g. never choosing high quality condoms for sex work), inter-personal level (e.g. agreement to have unprotected sex if fond of clients or paid more) and environmental/structural level (e.g. non-availability of condoms) were associated with various types of condom failure and improper use. 

Although HIV prevention interventions have increased prevalence of condom use among FSW, the risk of HIV transmission may still be high as "unsafe" sex due to condom failure and improper use is prevalent. Interventions promoting safer sex need to address such issues and take socio-ecological factors into account. 

Condom use during sex work is not equivalent to well protected sex as the protective effects could be compromised by frequent condom failure and improper use.

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By: Lau JT1, Zhou H, Su XY, Feng TJ, Hong FC, Tsui HY, Ma YL, Wang Z, Walden D.

• 1School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China.

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