Alarmingly high burden of STIs among people with HIV in rural Uganda

People living with HIV are 51% more likely to be diagnosed with at least one curable sexually transmitted infection (STI) than HIV-negative people, despite near universal HIV treatment coverage, a study in rural Uganda has found. Pregnant women living with HIV had an even higher rate of STIs.

The study, published in The Lancet Global Health, found that the most frequently curable STI with HIV in people with HIV was trichomonas, followed by active syphilis and gonorrhoea.

“Our results indicate that HIV programmes have failed to address non-HIV STI epidemics, especially among people living with HIV, and that these infections remain neglected diseases, ” comment the authors. “There is an urgent need to integrate STI care with HIV services in African settings.”

The study

Although HIV incidence has declined by 43% in eastern and southern Africa since 2010, population-level data on STIs in the era of widespread biomedical HIV prevention has been lacking. Researchers from the Rakai Health Sciences Program, Uganda, conducted a cross-sectional study nested within a population-based cohort in 2019 to measure the prevalence of five STIs.

A total of 1,825 participants aged 18 to 49 from southern Uganda with a median age of 32 years were enrolled in the study. A total of 919 were residents of an inland semi-urban agrarian community, while 906 belonged to a fishing community on the shore of Lake Victoria. Just over half were women (53%), of whom 107 were pregnant. HIV prevalence was 14% in inland communities and 40% in fishing communities, with about 90% viral load suppression among those living with HIV in both communities.

Blood samples were taken to test for HIV, herpes (HSV-2), and syphilis while genital swabs were collected for chlamydia, gonorrhoea and trichomonas testing.

Key findings

There was a total of 177 chlamydia, 122 gonorrhoea, 196 trichomonas, and 98 active syphilis infections detected among 26% of participants (n=478), of whom 21% had several infections.

Over a third of people living with HIV (36%) had a curable STI. They were 51% more likely to be diagnosed with at least one curable STI than those who were HIV negative (adjusted prevalence risk ratio (aPRR) 1·51, 95% confidence interval 1·27–1·78).

The prevalence of trichomonas was 9·4% in the inland community and 12·2% in the fishing community, with the burden significantly higher among women than men (16% vs 5%), and among people living with HIV relative to people who were HIV negative (17% vs 8·5%).

High-titre syphilis (suggestive of active infection) was substantially more common in the fishing community than in the inland community (9% vs 1%). Notably, 17% of men living with HIV in the fishing community had high-titre syphilis infection.

The prevalence of gonorrhoea was 5.0% in the inland community and 8.4% in the fishing community. Gonorrhoea prevalence was significantly higher among people living with HIV than those who were HIV negative (aPRR 1·93, 95% CI 1·30–2·86), except for women in the fishing community, for whom gonorrhoea prevalence was similar irrespective of HIV status.

Approximately one in ten people were diagnosed with chlamydia in both communities, and this was the only infection whose prevalence was lower among people living with HIV than those who were HIV-negative (6·6% vs 10·9%). Among men and women, chlamydia prevalence was highest among those younger than 30 years.

After infection, the herpes virus stays for life. HSV-2 seropositivity was highly prevalent in both communities, 43% in inland communities and 64% in fishing communities, and was strongly associated with HIV status. Women had a significantly higher prevalence of HSV-2 than men (63% vs 43%).

Untreated STIs can have serious consequences in pregnancy. Of the 107 pregnant women, 31% were diagnosed with chlamydia, 9% with gonorrhoea, 7% with trichomonas, and 3% with high-titre syphilis, with five women having several infections. Compared with pregnant women who were HIV-negative, pregnant women living with HIV were significantly more likely to have a curable STI (54% vs 24%); adjusted PRR 1·87, (1·10–3·17).

The authors urge the primary healthcare system in sub-Saharan Africa to integrate HIV and STI services. They say that the current approach of relying on symptoms to identify people with STIs is likely to miss many infections, and emphasise the need to introduce affordable, point of care STI diagnostics.