Detectable genital HIV shedding associated with cervical infections appears minimal among women taking ART

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Results from a small Kenyan study suggest that cervical HIV viral load levels remain low during episodes of cervical infection in HIV-positive women taking antiretroviral therapy (ART).

The finding is of interest to researchers exploring the dynamics of HIV infectiousness in the context of the global scale-up of ART, since viral load reductions resulting from ART usage in some settings may be of a large enough magnitude to bring about population-level reductions in HIV transmission.

Although ART greatly lowers infectiousness overall, detectable levels of HIV persist in the genital secretions of a small proportion of women taking ART.

Glossary

cervix

The cervix is the neck of the womb, at the top of the vagina. This tight ‘collar’ of tissue closes off the womb except during childbirth. Cancerous changes are most likely in the transformation zone where the vaginal epithelium (lining) and the lining of the womb meet.

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.

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.

shedding

Viral shedding refers to the expulsion and release of virus progeny (offspring such as competent particles, virions, etc.) following replication. In HIV this process occurs in the semen, the vaginal secretions and other bodily fluids, making those fluids more infectious.

prospective study

A type of longitudinal study in which people join the study and information is then collected on them for several weeks, months or years. 

The fact that cervical infections can increase genital HIV shedding in women not taking ART raises the question of whether the same dynamic might continue operating to some degree in women after they initiate treatment.

The Kenyan study indicates that this is not generally the case. Most study participants who developed cervical infections while taking ART were found to maintain undetectable cervical HIV viral load levels during those episodes. Among the small number of women whose viral load levels surpassed the threshold of detection, viral load levels still remained quite low.

The prospective cohort study enrolled 147 HIV-positive Kenyan women who met standard clinical criteria for ART initiation. The women began taking standard first-line antiretroviral regimens and providing biological samples for monthly viral load and genital infection testing. The viral load threshold of detection was 100 copies/mL.

Researchers analysed data from 30 study participants who experienced 31 episodes of cervical infection at least one month after they had started ART. One case involved the diagnosis and treatment of chlamydia; 17, gonorrhea; and 13, non-specific cervicitis.

From a statistical standpoint, women’s likelihood of developing detectable HIV viral load levels increased with the onset of cervical infections. However, only five women actually had detectable viral load levels and cervical infections concurrently.

The women’s viral load levels ranged from 100 to 820 copies/mL during episodes of cervical infection (median, 115 copies/mL).

The median age of the study subset experiencing cervical infections was 36 (interquartile range, 31 – 38). ART pill counts indicated high treatment adherence levels.

The authors caution that although their results “further highlight the potential benefits of ART as a prevention strategy,” it is important to bear in mind that even low levels of HIV in genital secretions can potentially result in transmission to sexual partners.

Thus, the paper concludes, “identification and treatment of cervical infections may help to optimize the secondary [HIV] prevention benefits of ART.”

The Kenyan study, although too small to yield definitive findings, contributes another piece to the complex picture that is emerging in relation to the concept of HIV treatment also functioning as an HIV prevention tool.

If other researchers concur that cervical infections do not greatly increase HIV-positive women’s likelihood of transmitting the virus to sexual partners, then this can be ruled out as a potential factor in efforts to explain why some people on ART are at greater risk of transmitting the virus onward than are others.

References

Gitau RW et al. Effect of acquisition and treatment of cervical infections on HIV-1 shedding in women on antiretroviral therapy. AIDS, advance online publication, September 24, 2010.