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BHIVA 2015: HIV+ Men on Antiretroviral Treatment Have Undetectable Rectal Viral Load


A small study assessing the infectiousness of HIV-positive gay men taking antiretroviral therapy has found that all study participants had an undetectable viral load in the rectum, according to a presentation at the British HIV Association (BHIVA) conference last week in Brighton. Men who had rectal gonhorrea or chlamydia did not have detectable virus either, suggesting that concerns about sexually transmitted infections raising the risk of HIV transmission may be unfounded when people are taking effective HIV treatment.

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It has long been thought that untreated sexually transmitted infections can raise HIV viral load. For example, the 2008 "Swiss Statement" and its British equivalent have both advised that the protective effect of HIV treatment on onward transmission may not apply if either partner has a sexually transmitted infection. However, the interim results of the PARTNER study found no HIV transmissions at all from gay men taking HIV treatment, although 16% of the cohort had sexually transmitted infections while in the study.

The new data specifically concern rectal viral loads and rectal sexually transmitted infections. There are conflicting data about how high viral loads in rectal secretions are. A detectable rectal viral load would increase the risk of HIV transmission during anal sex without a condom when the man living with HIV is "bottom."

Researchers at Guy’s and St Thomas’ Hospitals in London recruited 42 HIV-positive men who have sex with men who were having sexual health check-ups.

  • 21 were taking antiretroviral therapy, including seven who had asymptomatic rectal gonorrhea or chlamydia.
  • 21 had never taken antiretroviral therapy, again including seven who had asymptomatic rectal gonorrhea or chlamydia.

Rectal swabs were tested for sexually transmitted infections, HIV viral load, and 10 inflammatory cytokines. Researchers hypothesize that inflammation could raise the risk of HIV transmission.

In all men taking antiretrovirals, rectal viral loads were undetectable (below 100 copies/mL). This included the 7 men with rectal gonorrhea or chlamydia, both before and after antibiotic treatment.

In men who had not used antiretrovirals, rectal viral loads were a median 2 log lower than their plasma viral loads. Having a sexually transmitted infection did not raise rectal viral loads or markers of inflammation, which were at similar levels to those of men taking antiretrovirals.

The findings suggest that gonorrhea and chlamydia have a minimal impact on onward HIV transmission, the researchers say.



O Davies, J Tiraboschi, S Costelloe, et al. Impact of rectal gonorrhoea and chlamydia on HIV viral load and inflammatory markers in the rectum; potential significance for onward transmission. 21st Annual Conference of the British HIV Association (BHIVA). Brighton, April 21-24, 2015. Abstract O19.