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STIs and HIV

Sexually transmitted infections (STIs) and HIV share a complex bidirectional relationship. HIV, with its attendant immunocompromise, often alters the presentation of STIs and affects their course1,2.

STIs: A harbinger of HIV acquisition and transmission

STIs such as Treponema pallidum (syphilis treponeme), Neisseria gonorrhoeae, Chlamydia trachomatis,

Trichomonas vaginalis, Mycoplasma genitalium, human papillomavirus (HPV) and herpes simplex virus type 2 (HSV- 2) infections, greatly increase the risk of acquiring or transmitting HIV infection (by two to three times, in some populations)2,7.

While STIs affect individuals of all ages, adolescents and young people are disproportionately affected. Apart from increasing the risk of HIV infection and transmission, STIs contribute adversely to sexual, reproductive, and maternal and child health1.

HIV complicates efficacious therapy and affects management strategies of some STIs. In South Africa, HPV infection and syphilis are major public health concerns. HPV is the most common STI and a major cause of cervical and other cancers4,6.


A recent South African study showed that HIV-positive status, having more than three lifetime sexual partners, having more than one sexual partner in the last month, more vaginal sex more than four times in the past month, and having a vaginal discharge currently/in the previous week increased the risk of high-risk HPV infection4.

HIV-positive women have a significantly higher risk of high-risk HPV prevalence than HIV-negative women (40.6% versus 21.4%). Moreover, studies have found higher high- risk HPV prevalence, high-risk HPV viral load, and cervical lesions among women who are HIV-positive compared to those who are HIV-negative3,4.

In men, the global prevalence rate of genital HPV infection is almost similar to that in women. The transmission rates being similar as well. Men who have sex with men, transgender women and HIV-infected men are at increased risk, with higher incidence rates (≥90%) of HPV anal infection than those in heterosexual men, in whom the number of sexual partners determines the risk of HPV infection5.

Apart from cervical and anal cancer, high-risk HPV is responsible for oropharyngeal (oral, tonsil, and throat areas) cancers and anogenital cancers, including vulvar, vaginal, and penile cancers5.

HPV preventive strategies is well established and include organised cervical screening programmes, and vaccinations. The vaccines work best if administered prior to exposure to HPV. Both these strategies have been shown to reduce the incidence of cervical cancer and mortality9,10,11.


Syphilis is a significant cause of preventable perinatal death. With only an estimated 72% of woman receiving screening for syphilis, many women may remain undetected and untreated6.


Untreated gonorrhoea can lead to several complications in the treatment of HIV. It can increase HIV viral load in genital fluids. However, individuals who are HIV-positive, on ART and have undetectable viral loads, are less likely to infect other individuals with HIV12.

In an HIV-negative individual, having gonorrhoea can make acquiring HIV more likely if they come in to contact with the virus. Symptoms of gonorrhoea usually appear between two and ten days after acquiring the bacteria12.

If left untreated, gonorrhoea can cause pelvic inflammatory disease (PID), long- term pelvic pain, infertility, and ectopic pregnancy. Untreated gonorrhoea may also cause testicular problems, potentially reduce fertility, can affect the joints, causing arthritic-like pain and swelling or skin rashes.

It can eventually spread to the bloodstream, leading to serious infection (septicaemia), which can be life-threatening12.


The protozoan Trichomonas vaginalis is responsible for trichomoniasis. T. vaginalis infects both men and women, although this unicellular parasite is more prevalent in women than men13.

Among people aged 15-49 years, it was estimated that in 2012 the global prevalence of T. vaginalis infection among women was 5% versus 0.6% among men13.

In summary, there is growing evidence that there is a need for special treatment considerations for T. vaginalis among women with HIV coinfection13.


Chlamydia is known as the silent STI due to its lack of symptoms in infected individuals particularly females. Chlamydia infection can lead to serious sequelae such as PID, tubal factor infertility, ectopic pregnancy, and chronic pelvis pain in women.

A South African study found that the overall prevalence of chlamydia among patients with HIV was 32.1%. The prevalence was significantly higher among females (39.2 %) compared to males (15.5%) patients and was highest among pregnant women followed by patients who had reported any allergic reaction. Among the HIV positive patients, the prevalence was higher among those who were not taking ARV (38.1%) compared to those who were taking them (28.5%).


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  8. South African National Department of Sexually Transmitted Infections Management Guidelines, 2018.
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