Papillomavirus infection is more common in young sexually active people. It is so prevalent that from 75% to 80% of this population will be infected in their lifetime. Most lesions will be eradicated spontaneously at the point of not being detected even with the most sensible methods. Persistent infections with oncogenic HPV increase intraepithelial neoplasia and cancer risks. Two ways of prevention may be proposed: screening for precursor lesions and immunization against HPV, to avoid them. Although anogenital cancer incidence is decreasing with screening methods, costs are high and emotional disturbance may be caused by an abnormal result. So, vaccines to prevent diseases associated to HPV must be available. In the last decade, clinical tests began with several vaccines targeting the most frequent HPV types. The goal of prophylactic vaccines is to prevent primary or persistent HPV infections, and thus prevent cervical cancer and/or genital warts and the aim of the therapeutic types is to prevent progression of HPV infection, induce regression of intraepithelial neoplasia or condylomata, or eradicate residual cervical cancer. Prophylactic HPV vaccines in late stages of clinical testing are composed of HPV L1 capsid protein that self-assemble into virus-like particles (VLPs) when expressed in recombinant systems, resulting in strong adaptive immune responses that are capable of neutralizing subsequent natural infections. Some studies observed 100% efficacy in preventing clinical disease for specific HPV types at least 5 years after immunization. Vaccines that target E6 and E7 proteins also represent an important strategy to control HPV-associated lesions and are in test in animal models. HPV vaccines seem to be more effective when administered prior to initiation of sexual activity, and vaccination campaigns should target preadolescent and adolescent populations. It is expected that with good coverage of the vaccine, 70% of cervical cancers will be prevented like other anogenital diseases caused by HPV infection.
Papillomavirus infections; Intra-epithelial neoplasia; Papillomavirus; Carcinoma, squamous cell