Human papillomavirus (HPV) is a highly contagious virus spread by skin-to-skin contact, including sexual intercourse or any contact with the genital area. Both women and men can be infected. Those infected may have no apparent symptoms or may develop genital warts, infection of the cervix, and cancer of the cervix, penis or anus. It is estimated that over 20 million Americans have HPV infection, and 75 to 80 percent of sexually active adults in the U.S. will acquire HPV infection before age 50, with peak incidence in the teen to 30-year-old age group.
HPV vaccination is given in a series of two doses (starting the series at 9 to 14 years) or three doses (starting the series at 15 years or older). Ideally, a woman should finish the vaccine series before her first sexual contact. However, the vaccine may benefit even those who have become sexually active or had HPV infection diagnosed in the past. The vaccine protects against the most aggressive strains of the HPV virus implicated in most cases of cervical cancer. The exact duration of protection is not known, but current studies indicate that the vaccine provides at least 10 years of protection. Side effects are minimal and include pain at the injection site.