Human papillomavirus (HPV) is a sexually transmitted infection (STI), also referred to as sexually transmitted disease (STD).

HPV is the most common STI in the United States. Almost 80 million Americans currently have HPV. About 14 million contract the virus each year.

More than 100 types of HPV exist. Because some are likely to cause more complications than others, the types are categorized as low-risk and high-risk HPV.

Low-risk types can’t cause cervical cancer and are treatable. High-risk types can cause abnormal cells to form on the cervix, which can develop into cancer if they’re left untreated.

Keep reading to learn more about the most common types of HPV.

If you’ve contracted HPV, identifying the type you have helps your doctor determine next steps. Some types of HPV clear up without intervention. Other types may lead to cancer. Your doctor will monitor your condition so that if cancer cells do develop, they can be detected early.

HPV 6 and HPV 11

HPV 6 and HPV 11 are low-risk types of HPV. They are linked to approximately 90 percent of genital warts. HPV 11 can also cause changes to the cervix.

Genital warts look like cauliflower-shaped bumps on your genitalia. They usually show up a few weeks or months after exposure from a sexual partner who has HPV.

Getting the HPV vaccine may help prevent HPV 6. The vaccine also offers some protection from HPV 11.

For the HPV vaccine Gardasil 9, clinical trials showed up to 89 to 99 percent effectiveness in protecting against HPV types 6 and 11. This significant reduction against contracting these types was noted in 9- to 26-year-olds.

The recommendation is to receive the vaccines prior to becoming sexually active, since the vaccine can’t protect against a strain of HPV that a person has already been exposed to.

If you do contract HPV 6 or HPV 11, your doctor can prescribe medications such as imiquimod (Aldara, Zyclara) or podofilox (Condylox). These are topical medications that destroy genital wart tissue.

This local destruction of the wart tissue helps enhance your immune system’s ability to fight the STI virus. You can apply these medications directly to your genital warts.

HPV 16 and HPV 18

HPV 16 is the most common high-risk type of HPV and usually doesn’t result in any noticeable symptoms, even though it can bring about cervical changes. It causes 50 percent of cervical cancers worldwide.

HPV 18 is another high-risk type of HPV. Like HPV 16, it doesn’t typically cause symptoms, but it can lead to cervical cancer.

HPV 16 and HPV 18 are together responsible for approximately 70 percent of all cervical cancers worldwide.

The HPV vaccine Gardasil 9 can protect against a number of types of HPV, including HPV 16 and HPV 18.

HPV testing can be performed for women with a Pap test (commonly known as a Pap smear), which is a screening test for cervical cancer. HPV testing is only available for women, and it can determine if HPV is present. If present, the test can determine whether the HPV is a low- or a high-risk type.

The HPV test isn’t recommended as routine screening for women under the age of 30. This is because many women will have some strain of HPV by that age. Most of these will clear spontaneously without intervention.

However, if a person’s Pap test showed abnormal cells, the HPV test would be done to assess their risk of more serious conditions, including cervical cancer.

If your test shows you have HPV, it doesn’t mean you’ll develop cervical cancer. It does mean that you could develop cervical cancer in the future, especially if you have a high-risk type of HPV. Your doctor will review your results with you and discuss treatment or surveillance options.

As mentioned above, 80 million Americans have HPV right now, and 14 million new diagnoses are expected each year. This means almost anyone who is sexually active will get at least one type of HPV during their lifetime.

It’s estimated that HPV will go away without treatment in 80 to 90 percent of people who contract the STI.

HPV infection is less common in women over the age of 30, but it’s more likely to lead to cervical cancer. This is one of the reasons why it’s important to see your gynecologist regularly.

Follow these tips to help prevent HPV:

Get the HPV vaccination

The HPV vaccine involves two shots, separated by 6 to 12 months, for those ages 9 to 14 years.

For people ages 15 and over, three shots are given over six months.

People between the ages of 27 and 45 who haven’t been previously vaccinated for HPV are now eligible for Gardasil 9.

Ask your doctor which vaccine they’re giving you

The types of HPV the different vaccines protect against vary:

  • The HPV bivalent vaccine (Cervarix) will only protect against HPV 16 and 18.
  • The HPV quadrivalent vaccine (Gardasil) will protect against HPV types 6, 11, 16, and 18.
  • The HPV 9-valent vaccine, recombinant (Gardasil 9) can prevent HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58.

Since Gardasil 9 protects against a much wider spectrum of HPV strains without a noted increase in side effects or adverse reactions, this choice offers more protection against HPV.

Common side effects of the Gardasil 9 vaccine is irritation at the injection site, including pain, swelling, or redness. Some people may have a headache following the injection.

Other tips

Avoid sexual contact with a partner if genital warts are present.

Use latex condoms every time you engage in sexual intercourse. But keep in mind that HPV is spread through skin-to-skin contact — not through exchange of bodily fluids. This means that while condoms may not always prevent the spread of HPV, they could reduce your risk.

If you’re a woman, make an appointment with your gynecologist for a cervical cancer screening. You should start screening at age 21 and continue until you’re 65.

HPV is very common. Most people with HPV don’t know they’re infected and experience no symptoms.

If you have HPV, it doesn’t mean you’ll develop cervical cancer.

However, knowing that you have a high-risk type of HPV will help you and your doctor come up with a plan to reduce your risk for cervical cancer.

You can do your best to prevent HPV by getting tested for cervical cancer if you’re a woman, and by keeping your vaccinations current.

Know the facts The American Cancer Society estimates that more than 13,000 women in the United States will be diagnosed with cervical cancer in 2018.