Incidence of sexually transmitted infections among adolescent's men who have sex with men and transgender women enrolled in a PrEP cohort study in Brazil


BACKGROUND: Adolescent men who have sex with men (aMSM) and transgender women (aTGW) are disproportionately affected by HIV and other sexually transmitted infections (STI). However, studies on the incidence of STI among adolescents enrolled in PrEP are still scarce. We aimed to estimate the incidence of N. gonorrhoeae, C. trachomatis, M. genitalium, M. hominis, U. urealyticum and U. parvum among adolescents PrEP users.
METHODS: PrEP1519 is a single-arm demonstration cohort study of daily TDF/FTC as PrEP. It is ongoing in 3 Brazilian capital cities among aMSM and aTGW aged 15-19 years-old (yo), recruited from February 2019-September 2021, with the following eligibility criteria: HIV uninfected, high risk of HIV, and with no risk of kidney and liver damage. They completed a questionnaire, and swab samples from multiple sites (oropharyngeal, anal, and urethral) were provider-collected and tested for each STI by using qPCR, at PrEP initiation and weeks 4, 12, and then quarterly through week 96. For this analysis, we included participants who had a minimum of 2 consecutive visits at the Salvador site and provided a swab sample at PrEP initiation and at least one more during follow-up. Case of STI was defined as positive-qPCR from any anatomical site. STI incidence rate per person-year (PY) of follow-up and 95% confidence intervals (95%CI) were estimated.
RESULTS: At PrEP initiation, participants were mostly MSM (91%) and 18-19 yo (84%). Median age of sexual debut was 14 yo (IQR:12-16), and 56% of participants did not use or did not remember using a condom at first sexual intercourse. Incidence measures of bacterial STI after initiating PrEP in Salvador (Brazil) are presented below. The incidence of U. urealyticum was particularly high.

Total NIncident casesSum of PYIncidence rate per 100 PY(95% CI)
N. gonorrhoeae
C. trachomatis
M. genitalium13711204.54.6(2.5-8.3)
M. hominis13319224.38.5(5.4-13.3)
U. urealyticum12843186.323.1(17.1-31.1)
U. parvum13710253.93.9(2.1-7.3)

CONCLUSIONS: Important rates of STI among adolescents in PrEP1519 indicate that innovative approaches to decrease STI incidence are much needed. Point-of-care STI testing should be an essential component to help decrease STI incidence among aMSM and aTGW PrEP users followed by appropriate STI treatment.

Download the e-Poster (PDF)