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In HIV-Discordant Gays, Viral Load Perception Strongly Linked to Unprotected Anal Sex
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7th IAS Conference on HIV Pathogenesis, Treatment and Prevention, June 30-July 3, 2013, Kuala Lumpur
Mark Mascolini
HIV-negative gays with an HIV-positive steady partner proved much less likely to have unprotected anal intercourse if they perceived their partner had a detectable viral load, according to results of a 76-couple cohort study in Australia [1]. But 7% of HIV-negative partners were wrong about their partner's viral load status or didn't know that status.
Studies of HIV transmission risk in HIV-discordant couples have predominantly involved heterosexuals. This research shows a lower transmission risk when the positive partner has a low or undetectable viral load. Opposites Attract is an ongoing longitudinal study of gay HIV-discordant couples in Australia. This analysis focused on viral load as perceived by the negative partner and risk behavior in 76 discordant couples.
Researchers recruit HIV-discordant couples into Opposites Attract via clinics and community-based advertising. Positive partners get a baseline viral load test, while negative partners get antibody testing for HIV. Negative partners also complete an online computer-assisted self-interview within 2 days of their study visit to report their sexual behavior and perception of their partner's viral load status. The investigators used logistic regression analysis to assess the association between unprotected (condom-free) anal intercourse (UAI) and viral load perception.
Through June 2013, Opposites Attract enrolled 76 couples with a median age of 38.1 in negative partners and 40.0 in positive partners. Fifty couples (65.8%) first had anal sex with each other more than 1 year before enrolling in the cohort. Eleven couples (14.5%) first had anal sex with each other 7 to 12 months ago, and 14 couples (18.4%) first had anal sex within the last 6 months. Half of these couples had sex outside the partnership in the past 3 months. One quarter of HIV-negative partners had UAI with someone other than their main partner and usually did not know that person's HIV status.
When the study began, 66 HIV-positive partners (87%) were taking antiretroviral therapy. Fifty-six HIV-positive partners (74%) had an undetectable viral load 20 (26%) had a detectable load. Sixty-one HIV-negative partners (80%) believed their positive partner had an undetectable viral load and 15 (20%) believed their partner had a detectable load or did not know their partner's load. So 5 HIV-negative partners (7%) were wrong or uninformed about their partner's viral load.
Fifty-five HIV-negative partners (72.4%) reported any UAI with their principal partner, including 48 (63.2%) who reported any insertive UAI, 32 (45.1%) who reported receptive UAI without ejaculation, and 19 (25%) who reported receptive UAI with ejaculation. During UAI negative partners took the insertive role more often than the receptive role.
Forty-nine of 61 negative partners (80.3%) who thought their positive partner had an undetectable load had UAI in the past 3 months. In contrast, 6 of 15 (40%) negative partners who thought their positive partner had a detectable load or did not know their partner's load had UAI in the past 3 months. In logistic regression analysis, a negative partner's belief that a positive partner had a detectable viral load lowered odds of UAI 84% (odds ratio 0.16, 95% confidence interval 0.05 to 0.55, P = 0.003).
All couples had a median 6 UAI acts in the past 3 months. The range of UAI acts in the past 3 months was vast: 0 to 183. In couples with a negative partner who thought his partner had an undetectable load, median UAI acts stood at 8. In couples whose negative partner thought his partner had a detectable load or did not know, median recent UAI acts stood at 0 (P = 0.011). Average number of UAI acts in couples with a perceived undetectable versus detectable or unknown viral load was 22.4 versus 10.2.
Median number of insertive UAI acts by negative partners who thought their positive partner had an undetectable load was 4, compared with a median of 0 in negative partners who thought their partner had a detectable load or did not know their partner's load. Respective median numbers of negative-partner receptive UAI without ejaculation were 1 and 0. In both groups median number of receptive UAI acts with ejaculation by HIV-negative partners was 0.
Thus HIV-negative men who believed their positive partner had a detectable load or did not know their partner's load tended to avoid all four types of UAI considered:
Median UAI with perceived undetectable load versus perceived detectable or unknown load:
-- Any UAI: 8 versus 0
-- Insertive UAI by negative partner: 4 versus 0
-- Receptive UAI by negative partner without ejaculation: 1 versus 0
-- Receptive UAI by negative partner with ejaculation: 0 versus 0
Opposites Attract investigators concluded that perceived undetectable viral load strongly predicts condom-free anal intercourse in HIV-discordant gay couples. Of course an undetectable plasma viral load does not guarantee an undetectable load in semen among gay men [2]. Also, this study showed that HIV-negative partners did not always correctly perceive their positive partner's viral load status.
References
1. Bavinton BR, Jin F, Zablotska I, et al. Undetectable viral load is associated with increased unprotected anal intercourse in gay serodiscordant couples. 7th IAS Conference on HIV Pathogenesis, Treatment and Prevention, June 30-July 3, 2013, Kuala Lumpur. Abstract MOLBPE30.
2. Ghosn J, Delobelle A, Leruez-Ville M, et al. Prevalence of HIV-1 seminal shedding in HIV-1 infected men who have sex with men and association with the size of intracellular HIV-1 reservoir (ANRS EP49). 52nd Interscience Conference on Antimicrobials and Chemotherapy (ICAAC). September 9-12, 2012. San Francisco. Abstract H-1570f. http://www.natap.org/2012/ICAAC/ICAAC_34.htm
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