[What clinicians should know about human papilloma virus vaccines]

Human papillomaviruses (HPVs) are epitheliotropic viruses that infect the basal layer of mucosal and keratinizing epithelia. HPV viral genome is made up of an early transcription region (E) and a late region composed of genes L1, L2, and a long control region (LCR). Despite the benign character of most lesions, HPV oncogenicity has been demonstrated in anal cancer, epidermodysplasia verruciformis, and cervical cancer. Nearly 12% of worldwide cancer incidence is due to HPV infection and HPV-16 is the most prevalent genotype found. Therefore, efforts in vaccines against HPVs have been directed mainly toward this genotype to dramatically diminish worldwide anogenital cancer incidence. Therapeutic vaccines are based on induction of an immunologic response against infected cells that express modified viral antigens E6 and E7. Prophylactic vaccines are based on prevention of infection by means of induction of humoral immunity against capsid viral proteins L1 and L2. This article reviews basics of the design of HPV vaccines and the type of vaccines currently being evaluated in clinical studies.