Photo Credit: Viktoriia Hnatiuk

Among transgender men, potential correlations between testosterone, Lactobacillus dominance, and lower PrEP medication concentrations in cervicovaginal fluid may impact HIV risk during vaginal sex, according to findings published in JAIDS. Elizabeth Hastie, MD, and colleagues noted that, among transgender men, little is known about PrEP efficacy and the biologic factors that impact HIV transmission. The researchers obtained cervicovaginal fluid samples from 13 transgender men—including seven on testosterone—and 32 cisgender women to examine the vaginal microbiome, medication concentrations, and inflammatory markers. The proportion of Lactobacillus in cervicovaginal fluid was significantly higher in cisgender women than in transgender men (78% vs 24%; P<0.001). In transgender men, the proportion of cervicovaginal Lactobacillus was lower, though not significantly so, in those taking testosterone versus not. Mean PrEP medication concentrations in cervicovaginal fluid were lowest in transgender on testosterone, though not statistically significantly so. “Future studies with larger sample sizes are needed to further investigate these relationships,” Dr. Hastie and colleagues wrote.