title: HPV vaccine cross-protection: Highlights on additional clinical benefit.
abstract: Prophylactic human papillomavirus (HPV) vaccines are administered in vaccination programs, targeted at young adolescent girls before sexual exposure, and in catch-up programs for young women in some countries. All the data indicate that HPV-virus-like particles (VLPs) effectively prevent papillomavirus infections with a high level of antibodies and safety. Since non-vaccine HPV types are responsible for about 30% of cervical cancers, cross-protection would potentially enhance primary cervical cancer prevention efforts. High levels of specific neutralizing antibodies can be generated after immunization with HPV VLPs. Immunity to HPV is type-specific. However, if we consider the phylogenetic tree including the different HPV types, we realize that a certain degree of cross-protection is possible, due to the high homology of some viral types with vaccine ones. The assessment of cross-protective properties of HPV vaccines is an extremely important matter, which has also increased public health implications and could add further value to their preventive potential. The impact of cross-protection is mostly represented by a reduction of cervical intraepithelial neoplasia CIN2-3 more than what expected. In this article we review the mechanisms and the effectiveness of Bivalent (HPV-16/-18) and Quadrivalent (HPV-6/-11/-16/-18) HPV vaccine cross-protection, focusing on the critical aspects and the potential biases in clinical trials, in order to understand how cross-protection could impact on clinical outcomes and on the new perspectives in post-vaccine era.
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Catholic University of the Sacred Heart, L.go A. Gemelli 8, 00168, Rome, Italy. rosa.devincenzo@rm.unicatt.it
authors.forename: Rosa
authors.initials: R
authors.lastname: De Vincenzo
authors.forename: Caterina
authors.initials: C
authors.lastname: Ricci
authors.forename: Carmine
authors.initials: C
authors.lastname: Conte
authors.forename: Giovanni
authors.initials: G
authors.lastname: Scambia
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D056738:Cross Protection / Q000276:immunology*; D005260:Female; D000068857:Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18; D006801:Humans; D027383:Papillomaviridae / Q000276:immunology*; D053918:Papillomavirus Vaccines / Q000191:economics / Q000276:immunology*; D002583:Uterine Cervical Neoplasms / Q000517:prevention & control* / Q000821:virology; D058425:Vaccines, Virus-Like Particle / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000068857:Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18; D053918:Papillomavirus Vaccines; D058425:Vaccines, Virus-Like Particle; C510352:human papillomavirus vaccine, L1 type 16, 18
keywords: Bivalent vaccine; Cross-protection; Human papillomavirus; Quadrivalent vaccine