High prevalence of anal papillomavirus infection in men who have sex with men PrEP users

Objectives Human papillomavirus (HPV) is the most common STI and is associated with a wide range of diseases from anogenital warts to malignancies. Anal HPV infection is considerably more common in men who have sex with men (MSM) living with HIV. Aims of the present study are to (i) describe the prevalence of anal HPV infection in MSM who started pre-exposure prophylaxis (PrEP) and (ii) analyse factors associated with anal infection from genotypes that would be covered by nonavalent vaccination. Methods This monocentric, cross-sectional study included all subjects who started PrEP from May 2018 to November 2021. PrEP candidates underwent full behavioural and clinical evaluation, including digital anal rectal examination and swabbing for HPV determination. Descriptive statistics, Mann-Whitney U test for continuous and χ2 tests for categorical variables were adopted. Unadjusted and adjusted regression analyses were performed to assess factors associated with positive anal swabs and to the presence of genotypes covered by the nonavalent vaccination. Results The analysis included 288 subjects: anal swabs tested positive in 87.2% of cases, 79.2% of the subjects had a high-risk genotype (mainly 16), whereas 67.4% had a genotype covered by nonavalent vaccine. Sexual role was the only factor associated with anal HPV infection. Use of recreational drugs and a diagnosis of ≥2 STIs correlated with the presence of genotypes that would have been covered by vaccine, while previous vaccination had a protective role. Conclusions PrEP candidates showed a high prevalence of anal HPV infection, especially due to high-risk genotypes, comparable to what has been reported in MSM living with HIV.