Human papillomavirus (HPV) is a virus from the papillomavirus family that establishes infections only in keratinocytes of the skin or mucous membranes. While the majority of the known types of HPV cause no symptoms in most people, some types can cause warts, while others can lead to cancers of the cervix, vulva, vagina, penis, oropharynx and anus.
The 13 types of high-risk HPV that are of most concern are known by the numbers 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68, and can cause abnormal cells to form that can develop into cancer if not treated. Types 16 and 18 are the most dangerous and cause 70% of cases of cervical cancer. In one study, the National Cancer Institute found that about 10 percent of women with HPV type 16 or 18 developed advanced, pre-cancerous cervical disease (CIN 3) within three years, and 20 percent did so in 10 years.
The 12 types of HPV considered low-risk cannot cause cervical cancer, but they can cause genital warts or very minor cell changes on the cervix. These low-risk types of HPV are known by the numbers 6, 11, 40, 42, 43, 44, 53, 54, 61, 72, 73 and 81. Types 6 and 11 – which are linked to about 90 percent of genital warts – are the most common.
It has been estimated that HPV infection accounts for approximately 5 percent of all cancers worldwide.
Some symptoms of HPV include: genital warts; a foul smell, mild irritation, burning, itching or pain in the vulva, or vagina pain with intercourse, and increased vaginal discharge and bleeding (which can be caused by injury to warts after sexual intercourse).
Up to 90% of HPV infections become undetectable by sensitive DNA detection methods within one or two years, even if they have caused mild abnormalities on a Pap smear or cervical biopsy. The median duration of new infections is typically 8 months.
Cervical cells can be tested to identify high-risk types of HPV that may be present. HPV DNA tests look for viral DNA from multiple high-risk HPV types and can detect the presence of a viral infection before any cell abnormalities become visible. The FDA has approved HPV DNA tests for follow-up testing of women with equivocal cell abnormalities on a Pap test, but there are currently no approved tests to detect HPV in men.
Despite how prevalent HPV is, invasive cancer occurs only is 8 out of 100,000 American women annually, and the vast majority of cases occur in women who have not had a Pap smear in the preceding 5 years. Patients diagnosed with dysplasia, or high-right HPV need to understand the importance of complying with the recommended treatment, in order to avoid the small, but real possibility of developing cervical cancer over time.
About 20 million people in the U.S. are infected with HPV at any time, according to the CDC. And three-fourths of sexually active people between ages 15 and 49 have been infected at some point in their lives, according to estimates from the American Social Health Association.
In many cases genital warts do not cause any symptoms, but they are sometimes associated with itching, burning, or tenderness.
HPV lives in the body's epithelial cells. These are flat and thin cells found on the skin's surface and also on the surface of the vagina, anus, vulva, cervix, penis head, mouth, and throat.
Often, people don't have any symptoms and the HPV infection goes away on its own.