Title : Effectiveness of Doxycycline as Post-exposure Prophylaxis (Doxy- PEP) for bacterial Sexually Transmitted Infections (STIs) among Men Who Have Sex with Men (MSM) in Central Florida
Abstract:
Bacterial sexually transmitted infections (STIs), particularly syphilis, gonorrhea, and chlamydia, have been rising among men who have sex with men (MSM) in the United States. This trend is concerning, as these infections can lead to severe health complications if left untreated, including infertility, neurological issues, and increased susceptibility to HIV transmission. Multiple factors contribute to this rise, with one key factor being the increasing uptake of pre-exposure prophylaxis (PrEP) for HIV prevention, which has been associated with increased condomless sexual activity. While PrEP has successfully reduced new HIV infections, its unintended consequence has been the increased transmission of bacterial STIs, necessitating alternative preventive strategies.
Post-exposure prophylaxis with doxycycline (Doxy-PEP) has emerged as a promising biomedical intervention aimed at reducing bacterial STI incidence among MSM. Doxycycline, a widely used antibiotic, has been investigated for its potential to prevent syphilis, gonorrhea, and chlamydia when taken after sexual encounters. While some clinical trials have suggested Doxy-PEP could significantly lower STI rates, its real-world effectiveness remains uncertain, particularly in regions with high STI prevalence and potential antibiotic resistance.
This study aimed to assess the effectiveness of Doxy-PEP in preventing bacterial STIs among MSM in Central Florida, a region experiencing rising STI rates. To achieve this, a de-identified dataset from Pineapple Health Clinic in Orlando, Florida, was analyzed, including 73 participants who received Doxy-PEP for bacterial STIs between July 1, 2022, and June 30, 2023. The study focused on determining STI incidence rates among those using Doxy-PEP and identifying any disparities between HIV-negative and HIV-positive individuals.
Findings revealed unexpectedly high rates of bacterial STIs despite the use of Doxy-PEP, particularly for syphilis. Contrary to prior research indicating a protective effect of Doxy-PEP, both HIV-negative and HIV-positive individuals in the study showed elevated rates of syphilis, with the HIV-positive cohort exhibiting significantly higher incidence rates. This suggests that Doxy-PEP may not be as effective in real-world settings as previously anticipated or that other behavioral or biological factors influence its efficacy.
Another critical finding was the discrepancy in gonorrhea incidence and resistance profiles. While Doxy-PEP showed promise in reducing syphilis and chlamydia in some trials, its effectiveness against gonorrhea remains questionable due to the bacterium’s ability to develop antibiotic resistance. The study noted differences in medication regimens and age demographics, particularly among HIV-positive participants, which may have further influenced the results. The older age of the HIV-positive cohort, potential differences in sexual behaviors, and variations in adherence to Doxy-PEP protocols could all have played roles in the observed outcomes.
Several limitations must be acknowledged, including the small sample size, the study’s reliance on a single healthcare clinic, and the investigational nature of Doxy-PEP. These factors limit the generalizability of the findings. However, the study underscores the necessity of tailoring STI prevention interventions to specific populations, taking into account local antibiotic resistance patterns and demographic differences. Future research should further explore these factors to develop effective strategies for reducing STI incidence among MSM in Central Florida and beyond.
