4CPS-114 Incidence of sexually transmitted infections in prep users: is there an increase?

<h3>Background and Importance</h3> According to the regulations, the criteria for accessing pre-exposure prophylaxis (PrEP) include having had a bacterial sexually transmitted disease in the last year. However, hepatitis C must also be considered a sexually transmitted infection and may constitute a criterion for indicating PrEP. At the same time, users must meet other criteria such as not using a condom. <h3>Aim and Objectives</h3> To analyse incidence of sexually transmitted infections (STIs) in PrEP users before and after starting to take emtricitabine/tenofovir-disoproxil-fumarate (FTC/TDF) in a third-level hospital. <h3>Material and Methods</h3> Retrospective observational study of PrEP users who started to take FTC/TDF from December 2019 to September 2024. Demographic data(sex,age), criteria to start, STIs before and after PrEP and use of condom were recorded, as well as discontinuations. Information was collected from the hospital’s information systems. <h3>Results</h3> 190 users, 98%men, 1.5%trangender-women, 0.5%cisgender-women, median age 40 years (21–63). All patients met the criteria for starting PrEP and maintained negative HIV-serology (100%), after a median follow-up of 21±11.51 months. 1 user had to discontinue until kidney function stabilised. 47%users had STIs recorded before taking FTC/TDF, being the most frequent Treponema pallidum (56%), associated to other infections like Chlamydia trachomatis or Neisseria gonorrhoeae (17%), in 1 case with hepatitis C virus (HCV). Other infections found were: Mycoplasma genitalium (3%) and hepatitis B virus, human papillomavirus (HPV) or herpes (1%). After taking prophylaxis, 57%users had STIs, mainly Chlamydia trachomatis (38%), 63%associated with other bacteria: Neisseria gonorrhoeae and Mycoplasma genitalium. There was a similar number of isolated infections by Treponema pallidum, Neisseria gonorrhoeae and Mycoplasma genitalium (18,5%). In addition, 3% became infected with HCV. Moreover, it was observed that of the people who did not contract any STI, 22%claimed not to have used a condom. It should be noted that 9% of patients lacked data about previous STIs so we could not analyse. Taking this into account, the users who did not contract any infection are similar before and after taking the PrEP. <h3>Conclusion and Relevance</h3> In our population, it can be shown that PrEP has been effective in preventing HIV infection.Despite STIs incidence has been similar before and after taking prophylaxis, use of condoms must be promoted to prevent further transmission of STIs. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest