Beginning Truvada (tenofovir disoproxil fumarate/emtricitabine) as pre-exposure prophylaxis (PrEP) is associated with an increase in the likelihood of being diagnosed with sexually transmitted infections (STIs) among transgender women and cisgender men who have sex with men (MSM). This finding, from a review of multiple studies of PrEP including thousands of participants, suggests that condom use declines in this population during the period immediately following embarking upon a regimen of Truvada for HIV prevention.
Publishing their findings in Clinical Infectious Diseases, researchers conducted a systematic review and meta-analysis of 17 studies on PrEP use among trans women and cisgender MSM published from 2014 to 2017. Eleven of the studies were conducted in the United States and 15 took place in high-income nations.
The studies included 6,671 participants, with a median group of 268 people and a range of 50 to 1,603. The length of follow-up ranged from three to 18 months and was a median six months. The participant age was 34 years, with a range of 18 to 70 years.
Eight studies including 4,388 participants reported data on STI diagnoses at entry into a study and at a follow-up visit. The pooled results indicated that starting PrEP was associated with a 1.24-fold increased risk of an STI diagnosis during follow-up, including a 1.39-fold increased risk of any rectal STI diagnosis and a 1.59-fold increased risk of any rectal chlamydia diagnosis.
The studies conducted in later years saw a stronger correlation between starting PrEP and STI diagnosis during follow-up. For those studies that conducted their final data collection during 2016 or 2017 (as opposed to 2014 and 2015), there was a 1.47-fold increased risk of any STI diagnosis during follow-up.
The studies saw high rates of repeat STI diagnoses among the participants.
Thirteen studies including 5,008 participants had data on changes in self-reported sexual behavior between individuals’ entry into their study and the study’s follow-up period. None of these studies saw any significant change in the proportion of participants who reported engaging in condomless sex. This finding is likely a reflection of the fact that many participants were already using condoms at a rate less than 100 percent when they entered their study.
However, these 13 studies did show evidence that during the follow-up period, an increased proportion of participants reported engaging in condomless receptive anal sex with at least 10 partners, condomless sex with an HIV-positive partner or a partner of unknown HIV status, and never using condoms during anal sex.
The study is limited by the fact that the sexual behavior data is based on self-report, which can be unreliable.
“Study findings suggest that STIs increase after participants commence PrEP,” the study authors concluded. “Of particular interest is the increase in [rectal] STIs, suggesting an increase in condomless receptive anal intercourse after participants commence PrEP…[T]aken together, the included studies suggest that PrEP use is associated with a decline in condom use for anal sex, especially among MSM already using condoms inconsistently.”
To read the study abstract, click here.