Trends of Anogenital Warts: A 32-Year Retrospective Observational Study (Italy, 1991-2022)

Background: Anogenital warts (AGWs) represent the most common clinical manifestation of human papillomavirus (HPV) infection. The analysis of AGW time trends helps to investigate possible changes over time and monitor the impact of HPV vaccines on HPV-associated morbidity. Methods: AGWs diagnosed from 1991 to 2022 at a centre belonging to the Italian STI Surveillance Network were analysed in terms of their numbers and the socio-behavioural characteristics of the patients and then compared over the course of three decades. The time trends, overall and by transmission category, were investigated by joinpoint analysis. Results: In total, 9781 AGWs were diagnosed [61.9% in men who have sex with women (MSW)]. Individuals aged 25-34 years (36.9%), those with one recent partner (52.0%), and those with no previous STIs (87.8%) accounted for the majority of diagnoses. The HIV prevalence among individuals tested for HIV was 136/3098 (4.4%, 95% CI: 3.7-5.2). AGW diagnoses showed a mild decrease from 1991 to 2004, followed by a significant increase up to 2013 (the highest peak over the entire study period) and a significant decline thereafter, until the most recent years. During 2011-2022, diagnoses in women who have sex with men (WSM) decreased for those aged up to 24 years-the age class that could potentially have included women vaccinated against HPV. Conclusions: AGWs have declined in recent years. The decrease in the proportion of diagnoses in young WSM may reflect the female immunisation campaign in Italy. Nonetheless, there is still a need to promote vaccine uptake to reduce the AGW burden.