Human papillomavirus, cervical cancer, and the vaccines.

How are human papillomavirus (HPV), cervical cancer, and the recently developed HPV vaccines associated with each other? Human papillomavirus is a highly prevalent infection that is easily and unknowingly transmitted because of its asymptomatic nature and long incubation period. Infection requires skin-to-skin contact and is typically sexually transmitted. More than one-half of sexually active women acquire HPV, making it the most prevalent sexually transmitted disease. Cervical cancer ranks second in deaths from cancer among women in developing countries and kills nearly 4000 women in the United States annually. Several types of HPV have been strongly linked to causing cervical cancer and genital warts. Those causing cervical cancer are considered high-risk types and those causing genital warts are considered low-risk types. Until recently, prevention strategies included abstinence, condom usage, and early detection with a Papanicolaou test (Pap smear). New developments have led to 2 vaccines aimed at preventing the viral infection. One is a quadrivalent vaccine preventing infection from 4 HPV types (HPV types 6, 11, 16, and 18) (Gardasil). It is approved in the United States and Europe for the prevention of HPV-associated cervical cancers and genital warts in females between the ages of 9 and 26 years old. The second is a bivalent vaccine preventing infection from 2 high-risk oncogenic HPV types (HPV types 16 and 18) (Cervarix). It is currently under study and not yet available in the United States. Both vaccines have proven highly effective at preventing infection from their corresponding HPV types. Of importance, neither vaccine is to be used for treatment. Vaccination does not replace routine cervical cancer screening with Pap smears, as the vaccines do not protect against all HPV types.