title: An anal cancer screening program for MSM in Italy: Prevalence of multiple HPV types and vaccine-targeted infections.
abstract: BACKGROUND
  Elevated HPV infection rates have been described in HIV-positive males, placing these subjects at high risk of anal neoplasia. Bivalent, quadrivalent, and nonavalent vaccines to prevent HPV infection have been developed, and recently proposed for gender-neutral immunization programs.
  
  
  OBJECTIVE
  In order to estimate the benefit that could be obtained by vaccination of HIV-positive men who have sex with men (MSM), we aimed at describing the frequency of multiple and vaccine-targeted HPV infections in MSM enrolled in an anal cancer screening program.
  
  
  METHODS
  The anal cancer screening program was conducted between July 2009 and October 2012. Mucosal anal samples were tested for HPV DNA using MY09/MY11 PCR primers and, if positive, genotyped using the CLART2HPV Clinical Array (35HPV types).
  
  
  RESULTS
  A total of 220 MSM were screened and 88.6% were positive for HPV DNA: in 86.5% at least one high-risk (HR) type was found and in 13% only low-risk (LR) HPV were found. Multiple infections accounted for 84.5% of HPV DNA-positive cases and overall 160 different HPV genotype combinations were recognized (only three combinations were detected in more than one patient each). Based on strain coverage, at least one vaccine-targeted HPV type was found in 38.9%, 64%, and 78.4% of cases when considering bivalent, quadrivalent and nonavalent vaccines, respectively. At least one HR vaccine-targeted strain was found in 39% of MSM for bivalent and quadrivalent vaccines, and in 64% of cases for nonavalent prevention.
  
  
  CONCLUSIONS
  Anal HPV infections in unvaccinated mostly HIV-infected MSM are highly prevalent. The majority of this population has multiple infections with an extremely heterogeneous number of genotype combinations. The nonavalent vaccine could theoretically have prevented a minimum of one HR HPV type in two thirds of subjects.
authors.affiliation: Laboratory of Virology, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Anna Rosa
authors.initials: AR
authors.lastname: Garbuglia
authors.affiliation: Clinical Department, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Gentile
authors.affiliation: Laboratory of Pathology, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Del Nonno
authors.affiliation: Clinical Department, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Lorenzini
authors.affiliation: Laboratory of Virology, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Lapa
authors.affiliation: Clinical Department, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Lupi
authors.affiliation: Clinical Department, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Pinnetti
authors.affiliation: Laboratory of Pathology, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Baiocchini
authors.affiliation: Clinical Department, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Libertone
authors.affiliation: Clinical Department, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Cicalini
authors.affiliation: Laboratory of Virology, INMI "L. Spallanzani", Rome, Italy.
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Capobianchi
authors.affiliation: Clinical Department, INMI "L. Spallanzani", Rome, Italy. Electronic address: adriana.ammassari@inmi.it.
authors.forename: Adriana
authors.initials: A
authors.lastname: Ammassari
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000821:virology; D001005:Anus Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D060085:Coinfection / Q000453:epidemiology / Q000821:virology; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D055088:Early Detection of Cancer / Q000379:methods*; D005838:Genotype; D060005:Genotyping Techniques; D018451:Homosexuality, Male; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D027383:Papillomaviridae / Q000145:classification* / Q000302:isolation & purification*; D030361:Papillomavirus Infections / Q000453:epidemiology / Q000821:virology; D053918:Papillomavirus Vaccines / Q000276:immunology*; D016133:Polymerase Chain Reaction; D015995:Prevalence
chemical_list: D004279:DNA, Viral; D053918:Papillomavirus Vaccines
keywords: HIV; Human papillomavirus; MSM; Multiple infections; Vaccine-targeted infection; Vaccines