Human papillomavirus, known as HPV, refers to a group of over 100 related viruses, according to WebMD. About 40 of the viruses are sexually transmitted viruses that spread through contact with skin, mucous membranes and fluids in the genital area, most often through intercourse or oral sex.
About 50 percent of people who have sex contract HPV, according to the U.S. Food and Drug Administration. HPV doesn't always cause symptoms, meaning some infected individuals pass on the virus without realizing it. The virus affects both men and women, with an increased risk for those with multiple sexual partners or those who have sex at an early age.
HPV doesn't always cause serious health problems or any problems at all, but certain types put the person at a higher risk for serious problems. Some types of HPV can lead to cancer in the cervix, vagina or anus, states the FDA. Other types of HPV cause genital warts.
The HPV vaccine is considered effective, and it is recommended for all males and females, according to the CDC. The vaccine is generally administered at age 11 or 12. Men up to age 21 and women up to age 26 have the option of a catch-up vaccine.