Human papillomavirus is caused by having oral, anal or vaginal sex with an infected person, according to the U.S. Centers for Disease Control and Prevention. HPV is the most prevalent sexually transmitted infection in the United States as of October 2014 and is so common that nearly everyone who is sexually active will get HPV at some point.
Most cases of HPV go away on their own, according to the CDC. HPV can cause genital warts or several types of cancers, including cancers of the vagina, vulva, anus and penis. In addition, it can cause oropharyngeal cancer, which is a cancer that affects the back of the throat, tonsils and tongue. The HPV strain that causes cancer is different from the strain that causes genital warts.
Vaccines that guard against HPV are available for both males and females. The HPV vaccine course consists of three shots administered over a period of six months. The CDC recommends vaccination for all boys and girls ages 11 and 12 years and catch-up vaccines for males up to age 21 and females up through age 26. In addition, gay or bisexual men through age 26 are also encouraged to be vaccinated if they did not get the vaccine previously.