Human Papilloma Virus

Dec 09, 2020

Human papillomavirus (HPV) is a group of more than 100 related viruses. Some types of HPV are considered high risk because they are associated with cancer. HPV tests detect the genetic material (DNA or RNA) of the virus.

Some types of HPV can cause skin warts, while other types can cause genital warts (also called condylomata). Genital HPV infection is one of the most common sexually transmitted diseases. According to the U.S. Centers for Disease Control and Prevention, about 79 million Americans are infected with HPV and over 14 million become newly infected each year.

Most HPV infections spread through oral, anal, or genital sex are short-lived and relatively benign. The low-risk types of HPV that cause genital warts can be diagnosed through visual inspection and, therefore, do not require testing. Some HPV tests detect the low-risk types of HPV that cause warts, but the tests are generally not recommended for that purpose.

There are at least 13 types of HPV (such as HPV-16, HPV-18, HPV-31, HPV-33, and HPV-45) that are considered high risk. They do not usually cause visible warts, but long-lasting (persistent) infections are the cause of most cases of cervical cancerand are linked to other, less common cancers, such as those of the vagina, mouth, throat (including the base of the tongue and the tonsils), penis, and anus.

High-risk HPV types 16 and 18 account for about 70% of cervical cancers in the U.S. Each year, more than 13,000 women in the U.S. develop cervical cancer and about 4,000 are expected to die from it. In addition, some studies have also shown that persistent oral infections with high-risk types of HPV are strongly associated with oral cancers, including cancer of the mouth and throat (oropharyngeal cancer). Anal cancer has also been linked to HPV types 16 and 18. These high-risk types can be detected with an HPV test. The test is primarily used to screen for cervical cancer or to identify women at risk of cervical cancer.


The HPV test is primarily used to screen for cervical cancer and/or identify women who may be at increased risk of cervical cancer. The test determines whether a woman’s cervical cells are infected with a high-risk type of human papillomavirus (hrHPV). Such an infection, if long-lasting, can cause changes in cervical cells that could lead to cervical cancer. Now that hrHPV infection is known to be the cause of most cases of cervical cancer, HPV testing has become an essential part of women’s health screening.

Currently, the American College of Obstetricians and Gynecologists (ACOG), the U.S. Preventive Services Task Force (USPSTF), and the American Cancer Society (ACS) recommend the following options for routine cervical cancer screening in average-risk women aged 30 to 65 years:

  • Co-testing with a Pap test and high-risk HPV test every 5 years (preferred), or

  • Pap tests every 3 years (acceptable)

Significant changes to these recommendations may be on the horizon, however. The U.S. Food and Drug Administration (FDA) approved a high-risk HPV test as a primary screening tool for cervical cancer, meaning it may be used without a Pap test. Individual health organizations have yet to update their screening recommendations, but an expert panel issued interim (temporary) guidelines in 2015. (Read Experts Offer Advice on hrHPV Testing as a Primary Screen for Cervical Cancer.) Among the recommendations:

  • The HPV test may be offered to women aged 25 to 65 without a Pap test.

  • If initial results are negative, women should be screened again no sooner than 3 years.

More information about the use of the hrHPV test as the primary means of screening for cervical cancer will be forthcoming as the risks and benefits are further evaluated.

Because HPV infections are relatively common in women younger than 25 and often go away without treatment or complications, HPV screening is not recommended. However, HPV testing may be used as a follow-up test in women between the ages of 21 and 29 years who have abnormal results on a Pap test known as “atypical squamous cells of undetermined significance” (ASCUS) [see Pap Test Terminology]. Results may be used to determine the need for colposcopy, a procedure that allows a health practitioner to visually inspect the vagina and cervix under magnification for the presence of abnormal cells.

What does the test result mean?

HPV test results and Pap test results go hand-in-hand when determining a woman’s risk for cervical cancer. Co-testing with an HPV test and Pap test, as recommended by current guidelines, can determine whether cervical cells are infected with a high-risk type of HPV and identify abnormal changes in cervical cells.

The following chart outlines the meaning of possible co-testing results and includes the American Cancer Society (ACS), American Society for Colposcopy and Cervical Pathology (ASCCP), and American Society for Clinical Pathology (ASCP) recommendations for follow up. Remember, co-testing is currently recommended for women aged 30 to 65 years.

Co-testing Results

What Results Might Mean

Recommended Follow Up

HPV test negative, Pap test normal

Cervical cancer risk is low at the present time.

Repeat co-testing in 5 years (or Pap test alone in 3 years)

HPV test positive, Pap test normal

Cervical cells are infected with a high-risk type of HPV, but no abnormalities found in cervical cells.

Option 1: Repeat co-testing in 12 months
Option 2: Test for presence of HPV-16 or HPV-18
– If HPV-16 and/or HPV-18 present, colposcopy recommended
– If HPV-16 and/or HPV-18 not present, repeat co-testing in 12 months

HPV test negative, Pap test result unclear (ASCUS)

No HPV infection; changes in cervical cells may be the result of infection, inflammation, or hormonal changes and are likely to clear up without treatment.

Repeat co-testing in 3 years

HPV test positive, Pap test result unclear (ASCUS)

Cervical cells are infected with a high-risk type of HPV. The infection is the likely cause of abnormalities in your cervical cells.

Colposcopy to examine cervical cells under magnification

HPV test negative, Pap test abnormal (low-grade changes)

No HPV infection; cause of abnormal cervical cells unknown

Option 1: Repeat co-testing in 12 months
Option 2: Colposcopy to examine cervical cells under magnification

HPV test positive, Pap test abnormal (low-grade changes)

Cervical cells are infected with a high-risk type of HPV, which is the likely cause of abnormal cell growth.

Colposcopy to examine cervical cells under magnification and treatment of precancerous growths, if present

If a Pap test is performed without an HPV test, the presence of abnormal cervical cells indicates the need to perform an HPV test to determine whether HPV infection is the cause of the cellular changes.

  • After a negative result on an initial hrHPV test, a woman should not be re-screened for 3 years.

  • A positive result for high-risk type HPV-16 or HPV-18 should be followed up with colposcopy.

  • A positive result for the other 12 high-risk HPV types, such as HPV-31 and HPV-45, should be followed up with a Pap smear.

    • A positive Pap smear would be followed up with colposcopy.

    • A negative Pap smear would prompt follow-up testing in 12 months.

The most common HPV test detects DNA from several high-risk HPV types but cannot identify the specific subtype(s) that are present. Other tests are able to tell whether there is DNA or RNA from HPV types 16 and 18, the two types that cause 70% of cervical cancers.

Treatment for HPV Infection

There is no treatment for the virus itself, but the body’s immune system is usually able to fight it off within a few years. There are treatments, however, for the diseases the virus causes. Genital warts can be removed using chemicals, by freezing them or burning them off electrically, or via surgery or lasers. For most people, this treatment will clear the warts. If warts return repeatedly, a health practitioner may try injecting them with the drug interferon. Untreated genital warts can disappear on their own, stay the same, or grow in size and number and cluster in large masses.

Precancerous growths on the cervix can be treated in a variety of ways, from cryosurgery that freezes and destroys abnormal cells to surgical removal of problem tissue. Catching cervical changes early is the key to avoiding cervical cancer, which is more difficult to treat.

Prevention and Vaccines

Although monogamy (having sex with only one partner) will not keep you from becoming infected with HPV if either of you has ever had sex with someone who was infected, limiting your number of sex partners will reduce your risk of infection.

Using condoms may reduce the risk of spreading HPV, but only the skin that is covered by or comes in contact with the condom is protected from HPV. The virus can infect any uncovered skin on the genitals, groin, thighs, anus, and rectum and possibly in the mouth.

The U.S. Food and Drug Administration (FDA) has approved three vaccines that protect against HPV.

  • Gardasil® protects against HPV types 6, 11, 16 and 18. (Types 16 and 18 cause 70% of cervical cancers, while types 6 and 11 cause about 90% of genital warts.)

  • Gardasil 9 protects against the same HPV types as Gardasil plus 5 additional types that cause about 15% of cervical cancers.

  • Ceravix® protects against HPV types 16 and 18.

All three vaccines are approved for use in girls and women 9 to 26 years of age, and the two Gardasil vaccines are approved for the prevention of genital warts in boys and men 9 through 26 years of age. The vaccines are given in 3 doses over a period of 6 months. The same vaccine should be used each time a dose is administered.

The American Academy of Pediatrics (AAP) recommends that both girls and boys receive the HPV vaccine series when they are 11 to 12 years old. The vaccine is also recommended for men up to 21 and women up to 26 years of age who did not receive it when they were younger.

The FDA says the vaccines are considered safe but are only effective if given before an initial exposure to the virus. AAP recommends that young people who are sexually active still receive the vaccination, as those already infected with one type of HPV infection may benefit from the protection against other types included in the vaccine.