Human papillomaviruses, or HPVs, are a group of related viruses with more than 100 identified subtypes. The National Cancer Institute reports that more than 30 different HPV types can infect the genital areas. Transmission of these HPV types from person to person requires sexual contact. HPV infection is extremely common, occurring in more than 70 percent of the population. Most infections cause no symptoms and disappear without treatment within a year or two. The U.S. Food and Drug Administration approved the vaccine Gardasil in 2006 for the prevention of cervical cancer and genital warts. Gardasil is not a therapeutic treatment for genital warts.
Genital Warts
Genital warts are noncancerous skin tumors that are associated with few symptoms besides itching. A review article in the Dermatology Online Journal says that more than one million cases of genital warts are diagnosed each year and two-thirds of those cases are in women. This source additionally reports that greater than 70 percent of people who have sexual relations with infected individuals develop genital warts. Genital warts may appear on the vulva, vagina, cervix and anus in women and on the urethra, penis, scrotum and anus in men. Warts appear several weeks or months after sexual contact with an infected person. The CDC notes that the types of HPV that cause genital warts are not usually the same types that cause cervical and anal cancers.
Common HPV Types
The Centers for Disease Control, or CDC, reports that HPV types 6 and 11 account for 90 percent of genital wart cases. The Gardasil vaccine protects against infection from both HPV types 6 and 11. Vaccination does not benefit individuals who have already been exposed to the types of HPV contained within the vaccine. Commonly, people with genital warts are infected simultaneously with multiple HPV types.
Uncommon HPV Types
The Dermatology Online Journal states that rarely, HPV types 16, 18, 31, 33 and 35 are associated with genital warts. Once a person is infected with a type of HPV, his immune system will prevent symptoms from a recurrent infection with the same HPV type; however, developing immunity to one type of HPV does not protect against other types of HPV. Therefore, genital warts can reappear in a person exposed to a different HPV type.
