About one in three young women taking part in an HIV prevention study in six African countries had a curable sexually transmitted infection (STI), researchers have found.
Most of the women who had an infection had no symptoms, meaning they could have gone untreated if health workers relied only on signs such as unusual vaginal discharge or genital sores.
The findings come from the INSIGHT cohort study, which followed 3,087 sexually active women aged 16 to 30 in South Africa, Eswatini, Kenya, Malawi, Uganda and Zambia. The women were offered daily oral pre-exposure prophylaxis (PrEP), a medicine taken to prevent HIV infection.
Among the 3,011 women who had STI test results when they joined the study, 30.9% had at least one of four infections tested for: chlamydia, gonorrhoea, trichomoniasis or syphilis.
Chlamydia was by far the most common. It was detected in 20.8% of the women. Gonorrhoea was found in 6.8%, trichomoniasis in 6% and syphilis in 4.4%.
Yet only 15.7% of women with a confirmed STI said they had recently experienced symptoms. For syphilis, the figure was just 2.3%.
The researchers say this is a problem for clinics that diagnose and treat STIs mainly by looking for symptoms. “Approximately 85% of women with prevalent and incident STIs did not report symptoms and would have been missed by syndromic management,” they wrote.
The problem did not end after the women entered the study.
At the six-month follow-up, 574 of 2,731 women tested had developed a new chlamydia, gonorrhoea or trichomoniasis infection. The researchers estimated an incidence rate of 49.3 infections per 100 person-years. Only 12.7% of those with a new infection reported symptoms.
Women who had an STI when they joined the study were also more likely to develop another infection. Their risk was about 80% higher than that of women without an STI at enrolment. Low and moderate alcohol use were also associated with a higher risk of a new STI.
The study found no evidence that having an STI affected whether women continued taking PrEP. PrEP refills and recent adherence were similar among women who had an STI at enrolment and those who did not.
For the researchers, the findings point to a gap in how STIs are detected in many African health systems.
Symptom-based diagnosis remains common because it is relatively cheap and allows health workers to treat patients immediately. But it can miss infections that cause no obvious signs. Laboratory tests can identify these infections, although the researchers note that some of the more sensitive tests are expensive and difficult to access in many African countries.
The researchers argue that HIV PrEP programmes could provide a useful place to offer STI testing because they already reach young women seeking HIV prevention services.
They are calling for simple and affordable diagnostic tests that can be used alongside PrEP and other reproductive health services.
The study was led by Irene Mukui and colleagues and published in Sexually Transmitted Infections.
IMAGE CREDIT