The Burden of STIs Among Individuals Using PrEP

Both globally and in the United States, rates of sexually transmitted infections (STI) have been growing at an alarming rate. A major concern is that there is limited integration of broader sexual health services within pre-exposure prophylaxis (PrEP) provision programs, where risk for STI transmission is likely to be elevated.

A new systematic review and meta-analysis study of the global epidemiologic characteristics of STIs among individuals using PrEP shines light on both STI prevalence at initiation and during PrEP use. Results of the study, published in JAMA Network Open, indicate a high burden of STIs among both individuals starting and persistently using PrEP.

Results suggest that PrEP provision is concentrated among those at high risk, but that more must be done to prevent STIs among those who persistently use the HIV prevention medication.

Investigators employed 9 databases to review studies reporting STI prevalence or incidence among PrEP users. Methodological quality of studies was evaluated using the Joanna Briggs Institute critical assessment tool for prevalence and incidence studies, and a random-effects meta-analysis was performed.

The study team assessed outcomes including pooled STI prevalence within 3 months of PrEP initiation and STI incidence after 3 months of PrEP use.

Out of 3325 potential articles identified, 88 ultimately met inclusion criteria. A total of 62 of the 88 studies took place in those defined as high-income countries, but 26 low- and middle-income countries were represented in the analysis.

"In resource rich settings, many PrEP programs already provide excellent comprehensive sexual health services, but globally there is a whole spectrum of how sexual health services are integrated into PrEP programs," Jason Ong, PhD, MMed, MBBS, FAChSHM, FRACGP, sexual health physician, associate professor at the University of Melbourne, and an author of the study told Contagion®.

In studies which reported a composite outcome of early syphilis, chlamydia, and gonorrhea, pooled prevalence was 23.9% (95% confidence interval [CI], 18.6%-29.6%).

Pooled incidence of studies reporting the composite outcome of early syphilis, chlamydia, and gonorrhea was 72.2 per 100 person-years (95% CI, 60.5-86.2 per 100 person-years).

The authors believe that growing interest in PrEP presents an opportunity to package HIV prevention with further sexual health services.

“There are opportunities for economies of scope and scale to control STIs by leveraging the growing infrastructure of PrEP delivery and access to higher-risk individuals. Synergistically, the identification of high-risk individuals with STIs can be a gateway for the provision of PrEP,” authors wrote.

"My study reinforces that our current PrEP programs are correctly identifying people at most risk for HIV and other STIs. This is a good thing because it can be very difficult engage with people at highest risk for HIV/STIs. Now, through PrEP programs, these vulnerable people are regularly engaged in a health system, every 3 months. This highlights an unprecendented opportunity to not only offer them protection against HIV but also more comprehensive sexual health services," Ong said.

In a European survey about barriers to PrEP, 18 countries that had not integrated PrEP into their national health systems cited concerns about impact on sexual behavior. Yet results of the JAMA meta-analysis suggest that STI risk behaviors may already be there among those who would initiate PrEP, prior to uptake.

“The high pooled prevalence of STIs among those starting PrEP reinforces the belief that we are reaching groups at high risk for HIV and STIs, and the high pooled incidence emphasizes the need for ongoing STI testing and treatment services because PrEP users remain at high risk for STIs,” study authors wrote.

Ong referenced several reasons that comprehensive sexual health services had not been integrated into PrEP provision in the past, ranging from the cost of STI treatment to the separation of funding for HIV from funding for STI programs. In addition, settings with limited resources may rely on treating only those with symptoms of STI, missing a substantial number of asymptomatic cases. He also pointed to the lack of point-of-care diagnosis.

"Currently most testing for STIs require a laboratory and could take days for results, we need better tests that can give rapid, accurate results within the same consultation so that people with STIs can be treated earlier and more accurately," Ong explained.

Having those better tests could be a key component in improving STI treatment on a global scale, at a time when STIs are on the rise.

"I want to stress the urgent need for investment in better diagnostics for STIs. Increasing the access to cheaper, faster and accurate diagnostics would be a key contributor to control our current STI epidemics around the world," Ong said.