Human papillomavirus (HPV) is a common infection that causes abnormal growth of tissue on the skin of the body. There are more than 100 types of HPV, some of which cause common warts found on areas like hands and feet. However, over 30 types are usually sexually transmitted and are known as genital human papillomavirus. Genital HPV is the most common sexually transmitted virus, according to the Centers for Disease Control and Prevention (CDC).

HPV should not be confused with genital herpes, another STD. Both are caused by viruses, but HPV may cause warts while herpes may cause blisters or sores. Both diseases often do not cause any symptoms. There is no cure for either disease, but in most cases, the body’s immune system will fight off HPV. With herpes, the virus lies dormant in the body and can cause future outbreaks. Unlike herpes, certain types of HPV cause cervical dysplasia (precancerous changes in the cervix) in a small percentage of women.

HPV is categorized as low-risk (which may cause genital warts) or high-risk (which can lead to precancerous changes in the cervix if untreated). Infection with certain high risk forms of HPV is a major cause of cervical cancer and is associated with other genital cancers (e.g., vulvular, anal).

Most sexually active people have been exposed to HPV at some point in their lives. The virus is transmitted by skin-to-skin contact with an infected person, usually through vaginal, oral or anal sex. Most people with HPV do not experience symptoms and do not know they are infected.

HPV is usually detected during a gynecological exam with a Pap smear, a test that detects changes on the cervix. Physicians may also perform an HPV test that identifies high-risk types of HPV.

In most cases, the body's immune system will successfully fight off the infection. However, there are several treatments available when HPV causes warts, such as creams, cryotherapy and electrocautery.

In June 2006, the U.S. Food and Drug Administration (FDA) approved the first HPV vaccine. The vaccine offers protection against two types of HPV that cause the majority of cervical cancers. The federal Advisory Committee on Immunization Practices (ACIP) recommends the vaccine series be given to 11- and 12-year-old girls but it adds that it could be started as early as age nine if necessary. Ideally, the vaccine should be given before females become sexually active. Their recommendations also include giving the vaccine to young women ages 13 to 25 years because of its protective benefits. The HPV vaccine is expected to be available in the fall of 2006. It is considered to be the best prevention method of genital HPV for females.

Practicing safe-sex habits can also prevent infection with genital HPV. Limiting the number of sexual partners and avoiding genital contact with individuals who have had multiple sex partners reduces the risk of infection. In addition, condoms provide some protection but transmission is possible from areas not covered by the condom.