Men taking HIV treatment have undetectable viral loads in the rectum; sexually transmitted infections make no difference

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. Men who had rectal gonhorroea or chlamydia didn’t 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.

The data were presented to the British HIV Association conference in Brighton yesterday. 

It has long been thought that untreated sexually transmitted infections can raise HIV viral loads. For example, the ‘Swiss Statement’, and its British equivalent have both advised that the protective impact 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.

Glossary

rectum

The last part of the large intestine just above the anus.

chlamydia

Chlamydia is a common sexually transmitted infection, caused by bacteria called Chlamydia trachomatis. Women can get chlamydia in the cervix, rectum, or throat. Men can get chlamydia in the urethra (inside the penis), rectum, or throat. Chlamydia is treated with antibiotics.

detectable viral load

When viral load is detectable, this indicates that HIV is replicating in the body. If the person is taking HIV treatment but their viral load is detectable, the treatment is not working properly. There may still be a risk of HIV transmission to sexual partners.

inflammation

The general term for the body’s response to injury, including injury by an infection. The acute phase (with fever, swollen glands, sore throat, headaches, etc.) is a sign that the immune system has been triggered by a signal announcing the infection. But chronic (or persisting) inflammation, even at low grade, is problematic, as it is associated in the long term to many conditions such as heart disease or cancer. The best treatment of HIV-inflammation is antiretroviral therapy.

asymptomatic

Having no symptoms.

The new data specifically concern rectal viral loads and rectal sexually transmitted infections. There are conflicting data on 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 men who have sex with men living with HIV who were having sexual health check-ups.

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

Rectal swabs were tested for sexually transmitted infections, HIV viral load and ten inflammatory cytokines. (It’s hypothesised 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 seven men with rectal gonorrhoea or chlamydia, both before and after antibiotic treatment.

In men who hadn’t used antiretrovirals, rectal viral loads were a median 2 log10 lower than their plasma viral loads. Having a sexually transmitted infection didn’t raise rectal viral loads or markers of inflammation, which were at similar levels to those taking antiretrovirals.

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

References

Davies O et al. Impact of rectal gonorrhoea and chlamydia on HIV viral load and inflammatory markers in the rectum; potential significance for onward transmission. BHIVA conference, Thursday 23 April 2015, abstract O19. (Presentation slides available here).