Changing epidemiology and clinical presentation of rectal lymphogranuloma venereum in the HIV-PrEP era: A comparative study from Bologna, Italy

Introduction: Lymphogranuloma venereum (LGV), caused by Chlamydia trachomatis (CT) serovars L1-L3, has re-emerged in Europe since the early 2000s, predominantly affecting men who have sex with men (MSM), particularly people living with HIV (PLWH). The widespread implementation of HIV pre-exposure prophylaxis (HIV-PrEP) and the associated expansion of sexually transmitted infection (STI) screening programmes may have influenced the epidemiology and clinical presentation of LGV. Methods: We analysed the clinical and epidemiological characteristics of rectal LGV cases diagnosed in the Bologna metropolitan area during the HIV-PrEP era (2022-2025) and compared them with those of a historical cohort from the pre-HIV-PrEP era (2016-2020). Results: Overall, 93 rectal LGV cases were identified during 2022-2025, all among MSM, with a median age of 37 years; 66% were symptomatic, 48% were HIV-positive, 31% had concurrent rectal Neisseria gonorrhoeae infection, and 21% were diagnosed with early syphilis. Although the absolute number of LGV cases was higher than in 2016-2020 (93 vs 76), this difference occurred in the context of a substantial increase in anorectal CT testing during the HIV-PrEP era. Accordingly, LGV prevalence among anorectal swabs declined markedly (from 4% to 0.7%). When stratified by population group, HIV-PrEP users with LGV (n = 38) were younger than non-HIV PrEP users (n = 55, including 45 PLWH and 10 non-HIV MSM) and were significantly more likely to be asymptomatic, with lower rates of concurrent bacterial STIs. Conclusion: These findings suggest that rectal LGV remains endemic in our setting but may present with different clinical patterns in the HIV-PrEP era, with a higher proportion of asymptomatic infections among PrEP users, likely reflecting intensified STI screening. Continued epidemiological surveillance is needed to better understand LGV transmission dynamics and to inform tailored prevention and screening strategies among MSM.