Human papillomavirus (HPV) is the most common sexually transmitted disease. Almost everyone who has ever had sex will get HPV at some point, though most people never know they’re infected. That’s because most HPV infections go away on their own. However, others can cause warts or even cancer in men and women.
People can spread HPV to others during vaginal, anal, or oral sex, regardless of whether the infected person has any symptoms. Because HPV is so common, even having sex with just one person can lead to an infection. Signs or symptoms of HPV can also occur many years after someone is exposed to it.
There are more than 200 different HPV viruses. Most strains are low-risk and cause no disease. However, about 14 types of HPV are high-risk and can stay dormant for years without going away. Some of these will go on to develop cancer in men and women as much as 10 or 20 years after infection.
It’s not possible to prevention all HPV infections, but a vaccine can prevent several of the most dangerous strains. Doctors can also treat warts caused by HPV and screen for one of the cancers caused by HPV. People can also make a few changes to their behavior to reduce their risk of catching HPV.
Recognizing and Treating Genital Warts
Some HPV strains cause warts (small bumps) on your mouth, penis, scrotum, vagina, cervix, or anus. They can be big or small, may be round or cauliflower-shaped, and may even be flat. The warts might look flesh-colored, red, or darker or lighter than your skin, and they may be painless, itchy, or sore.
Doctors can prescribe medication for these warts, or they may go away on their own. Several other medical procedures can also remove warts, such as laser surgery or freezing them off with liquid nitrogen. Sometimes warts may come back even after being removed or going away.
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HPV and Cancer
The Centers for Disease Control and Prevention (CDC) estimates about 79 million people in the U.S. currently have an HPV infection. Most of these people are in their teens or twenties and will never develop cancer from their infection. However, about 25,000 women and 19,000 men develop cancer each year from HPV, according to a 2019 study from the CDC.
HPV is the leading cause of six different types of cancers:
- Cervical cancer
- Mouth and throat cancer (oropharyngeal)
- Anal cancer
- Penile cancer
- Vaginal cancer
- Vulvar cancer
More than 90% of cervical cancers develop from an HPV infection, according to the CDC. Infections from HPV also cause about 75% of all vaginal cancer and 70% of all vulvar cancer in women. In men, more than half of cancer in the penis results from HPV, although this type of cancer is very rare.
Anal cancer caused by HPV develops in about 4,200 women and 2,000 men in the U.S. every year. The most common HPV-caused cancer in men is oropharyngeal cancer, which occurs in the back of the throat. More than 11,000 men and 2,000 women each year receive a diagnosis of oropharyngeal cancer.
Preventing HPV Though Vaccination
The HPV vaccine protects against nine types of HPV, including the two types that are most likely to cause cancer (HPV16 and HPV18). The vaccine also protects against other strains that can cause cancer or warts.
The CDC recommends boys and girls receive two doses of the HPV vaccine at ages 11 or 12. Experts recommend vaccination at these ages because the vaccine is most effective when given before someone becomes sexually active. Children can get the vaccine as young as age 9, and the earlier they get it, the stronger its protection is.
The CDC recommends everyone get the vaccine by age 26. Some people may need three doses of the vaccine depending on when they got their first dose. People ages 27 to 45 can choose to get the vaccine after talking to their doctor about whether it would benefit them.
Screening for HPV-Related Cancers
Only one type of cancer caused by HPV has recommended screening procedures: cervical cancer.
Every year, about 200,000 women in the US develop abnormal cells on their cervix that can turn into cancer if not treated. About 11,000 new cases of cervical cancer occur each year in the US, and about 4,000 women die from cervical cancer annually.
Besides detecting cervical cancer, these screenings can also identify abnormal cells, so they can be treated before they turn become cancerous.
Women between ages 21 to 65 should undergo cervical screening every three to five years, depending on their age and the type of screening. For women ages 21 to 29, the U.S. Preventive Services Task Force recommends screening every three years with cytology, or a Pap smear. Pap smears involve scraping a sample of cells from the cervix so doctors can examine them under a microscope.
Women ages 30 to 65 have three choices for cervical cancer screening:
- Pap smear screening every three years.
- HPV testing every five years for high-risk strains of HPV. (There are many types of HPV but most are harmless. Testing for all, rather than just the high-risk strains, would lead to a lot of positives that scare people unnecessarily.)
- Co-testing with Pap smear and high-risk HPV testing every five years.
You should speak to your doctor about which screening program is best for you.
Cervical Cancer: Screening, US Preventive Services Task Force. Link
Eileen M. Burd. Human Papillomavirus and Cervical Cancer. Clinical Microbiology Reviews. January, 2003. Link
Genital HPV Infection - Fact Sheet, Human Papillonavirus (HPV), Centers for Disease Control and Prevention. Link
Genital Warts (venereal warts, HPV), New York Department of Health. Link
HPV and Cancer, National Cancer Institute. Link
HPV Diseases and Cancers, Human Papillonavirus (HPV), Centers for Disease Control and Prevention. Link
HPV Vaccine Recommendations, Vaccines and Preventable Diseases, Centers for Disease Control and Prevention. Link
Vaccinating Boys and Girls, Human Papillonavirus (HPV), Centers for Disease Control and Prevention. Link
About Infectious Diseases
If you have a disease caused by bacteria, fungi, parasite, or virus, the UPMC Center for Care of Infectious Diseases can help. Our team of experts is specially trained in the prevention and treatment of infectious diseases, including of HIV-AIDs, postsurgical and transplant infections, illnesses caused by international travel, and more. We research infectious diseases and participate in clinical trials to learn more and develop better treatment and prevention methods. Visit our website to find an expert near you.