Research Summary

Increased Prevalence of STIs Among Patients Undergoing PrEP Testing

Leigh Precopio

Higher rates of sexually transmitted infections (STIs) were observed in individuals undergoing diagnostic panels to begin pre-exposure prophylaxis (PrEP) for HIV when compared with the general population, according to the results of a study presented at the International AIDS Conference 2022.

Researchers conducted a retrospective database analysis of PrEP panels ordered for 2316 patients between August 2019 and December 2021. Of these patients, 332 patients had more than one panel ordered.

Included were PrEP baseline panels, which tested for HIV-1, syphilis, chlamydia, gonorrhea, hepatitis B, and hepatitis C and PrEP monitoring panels, which tested for HIV-1, syphilis, chlamydia, and gonorrhea. Combined data from both panels were used to determine prevalence of infection.

HIV-1 infection was present in 2.7% of patients, chlamydia in 4.1% of patients, and gonorrhea in 2.2% of patients. Active syphilis and hepatitis C infections were seen in 9.7% and 1.3% of patients, respectively. Further, 7.1% of patients had previously treated or early syphilis infections, and 7.2% had prior hepatitis C infections.

There was no evidence of exposure or immunity to hepatitis B in 47% of patients. Evidence consistent with hepatitis B virus vaccination was seen in 38% of patients. Recovery of hepatitis B infection was observed in 13% of patients and 1% had an active hepatitis B virus infection, as determined by biomarkers.

In patients with more than one panel ordered, HIV-1 infection was observed in one patient, syphilis in 1.8%, chlamydia in 2.2%, and gonorrhea in 0.6% of patients. None of these patients had hepatitis C or B infections. The most frequent coinfections with HIV-1 include syphilis (1.2%), chlamydia and gonorrhea (0.3% each), active hepatitis C (0.2%), and hepatitis B (0.06%).  

“The prevalence of STIs in patients with PrEP testing was high compared to the general population,” the researchers concluded. “These findings may reflect a bias toward testing symptomatic individuals and/or high-risk behavior in this patient group. Continued vigilance for STIs, even among asymptomatic PrEP users, is warranted.”



Curanovic D, Walworth C. Prevalence of viral and bacterial STIs in patients with PrEP testing. Paper presented at: International AIDS Conference 2022; July 29-August 2, 2022; Montreal, Canada. Accessed January 5, 2023.