High incidence of sexually transmitted infections (STIs) in pre-exposure prophylaxis (PrEP) trials has led clinicians and public health advocates to be concerned that PrEP use might lead to higher STI incidence and antibiotic resistant STIs due to increased sexual risk behavior.
A literature review was conducted on PubMed with the following inclusion criteria: (1) English-language, (2) cohort of MSM, and (3) STI incidence rates reported with nucleic acid amplification testing. OpenMetaAnalyst was used for a meta-analysis to calculate the overall risk of incident STIs and StataSE was used to calculate incidence rate ratios comparing incident STIs in studies of MSM on PrEP versus MSM not using PrEP.
We identified over 70,000 person-years of follow-up time in 18 cohort studies of MSM with incidence rates of STIs. Incidence rate ratios showed that MSM using PrEP were 25.3-times more likely to acquire a Neisseria gonorrhoeae infection, 11.2-times more likely to acquire a Chlamydia trachomatis infection, 44.6-times more likely to acquire a syphilis infection, and 9.2-times more likely to acquire any STI when compared with MSM not using PrEP.
Our analyses found that PrEP was associated with increased risk of STI acquisition, which could lead to increased transmission of STIs and antibiotic resistant STIs. Limitations of our analysis include utilization of studies with heterogeneous populations, different frequencies of STI screenings, differences in diagnostic tests used, and population level STI prevalence. Also, PrEP studies recruited MSM with high-risk sexual behavior whereas studies in MSM not using PrEP may have had different baseline risk behavior.
Our results support updating current CDC guidelines to recommend quarterly STI screening in MSM using PrEP. While PrEP may be associated with increased STI incidence, the benefit of HIV prevention may outweigh its impact on other STIs. Therefore, physicians must not only vigilantly identify patients that may benefit from PrEP, but also provide their patients with a sexual health prevention package that includes STI screenings every three months, expedited partner treatment, rescreening if positive, and promotion of consistent condom use.
J. Klausner, None