The human papillomavirus (HPV) is one of the most common sexually transmitted diseases in the United States, with more than 20 million Americans currently infected, according to the CDC.
HPV is most common in women and men in their late teens and early 20s. HPV is so common that at least 50 percent of sexually active men and women get it at some point in their lives. Learning about HPV can help you avoid infection and seek treatment, if necessary.
Many types of HPV infection cause no symptoms. For some types of HPV, the most visible symptoms are genital warts, which can be found on the penis and around or inside the anus in men, and on the vulva, around or inside the anus, inside the vagina, and on the cervix in women. HPV warts are usually small, flesh-colored, and flat or bumpy growths that appear singly or in clusters and can have a cauliflower-like appearance. They don’t often cause pain but may cause itching. Warts inside the vagina or anus or on the cervix aren’t visible and may not cause any symptoms.
HPV is usually transmitted through vaginal, oral, or anal sexual intercourse with a person who has the virus. It can also be passed on through skin-to-skin contact that doesn't involve penetration of the anus or vagina. Because HPV infection often shows no symptoms, it’s impossible to tell just by looking if a person has genital HPV. Also, a person may have no idea he or she has HPV, because there may be no symptoms.
In 2006, the FDA approved the first vaccine to prevent infection with certain strains of HPV. Several strains of HPV have been identified. The vaccine, Gardasil, protects against strains 16 and 18, which cause about 70 percent of cervical cancers, and against types 6 and 11, which cause about 90 percent of genital warts. The vaccine does not protect against HPV strains 31 or 45, which can also cause cervical cancer. The vaccine, which does not contain live virus, is approved for females and males ages 9 to 26.
In 2006, the Advisory Committee on Immunization Practices recommended the vaccine for three age groups: all girls between 11 and 12; girls and women 13 to 26 years old who have not received the vaccine; and women who have had abnormal Pap smears up to the age of 26, genital warts, or certain other conditions. However, the vaccine may also be given to women above the age of 26 if they have had an abnormal Pap smear. In 2011, the vaccine was approved for use in boys and men. The CDC recommends that boys be vaccinated between ages 11 and 12, or between ages 13 and 21 if they were not vaccinated earlier. The vaccine is approved for use in men up to age 26 years, and is recommended for men who have sex with men.
Another HPV vaccine called Cervarix, which protects against HPV strains 16 and 18 only, is also approved for use in women ages 9 to 26. Cervarix does not protect against HPV strains causing genital warts, and is not approved for use in boys or men.
Both brands of vaccine are given in three doses over six months. If a woman is already infected with one of the HPV strains included in the vaccine, the vaccine can't protect her from the effects of the strain she already has. It also will not protect against infection with other HPV strains, so regular Pap tests are still important, the FDA says.
A person who becomes sexually active at a young age and/or has sex with many partners has a greater risk of getting HPV infection. Having sex with someone who has had many partners also increases the risk. It’s important for sexual partners to discuss their sexual history and any sexually transmitted diseases they may have or have had.
The best way to reduce the risk is to get vaccinated against HPV; using condoms also can reduce the risk.
In men, HPV is often diagnosed when warts are seen on the penis surface. HPV is often more difficult to diagnose in women because it’s hard to detect or feel for warts inside the vagina or on the cervix. It’s important for women who are sexually active to have regular pelvic exams and Pap tests with or without HPV tests.
If a woman under age 30 has an abnormal Pap smear, she can have a test to determine if she has one of the HPV strains that can cause cancer. The results of this HPV test and the Pap smear can help determine if further tests such as colposcopy (examination of the cervix using an instrument that magnifies the cells of the cervix) and cervical biopsy are needed.
In most cases, the body’s immune system will eliminate the virus within two years of infection. If the immune system cannot eliminate the virus, there are currently no drugs or treatments that can kill it. Warts can be treated by applying a cream, freezing them off, using a laser, or removing them surgically.
The vaccine cannot protect against all strains of HPV that cause cancer. Although HPV infection is the main risk factor for cervical cancer, most women who have been infected with HPV don’t get cervical cancer, and treating genital warts may be all that is needed. Certain other risk factors, such as smoking or a weakened immune system, may influence which women with HPV infections are more likely to develop cervical cancer.
Seeing a health care provider for regular checkups if you’re sexually active can help you get treatment for HPV early, when it’s easier to treat.