Human Papillomavirus (HPV) Infection

Approximately 100 types of human papillomavirus infection (HPV) have been identified, at least 40 of which can infect the genital area (758). Most HPV infections are self-limited and are asymptomatic or unrecognized. Most sexually active persons become infected with HPV at least once in their lifetime (533,759). Oncogenic, high-risk HPV infection (e.g., HPV types 16 and 18) causes most cervical, penile, vulvar, vaginal, anal, and oropharyngeal cancers and precancers (760), whereas nononcogenic, low-risk HPV infection (e.g., HPV types 6 and 11) causes genital warts and recurrent respiratory papillomatosis. Persistent oncogenic HPV infection is the strongest risk factor for development of HPV-associated precancers and cancers. A substantial burden of cancers and anogenital warts are attributable to HPV in the United States: in 2009, an estimated 34,788 new HPV-associated cancers (761,762) and approximately 355,000 new cases of anogenital warts were associated with HPV infection (763).

Prevention

HPV Vaccines

There are several HPV vaccines licensed in the United States: a bivalent vaccine (Cervarix) that prevents infection with HPV types 16 and 18, a quadrivalent vaccine (Gardasil) that prevents infection with HPV types 6, 11, 16, and 18, and a 9-valent vaccine that prevents infection with HPV types 6, 11, 16, and 18, 31, 33, 45, 52, and 58. The bivalent and quadrivalent vaccines offer protection against HPV types 16 and 18, which account for 66% of all cervical cancers, and the 9-valent vaccine protects against five additional types accounting for 15% of cervical cancers. The quadrivalent HPV vaccine also protects against types 6 and 11, which cause 90% of genital warts.

All HPV vaccines are administered as a 3-dose series of IM injections over a 6-month period, with the second and third doses given 1–2 and 6 months after the first dose, respectively. The same vaccine product should be used for the entire 3-dose series. For girls, either vaccine is recommended routinely at ages 11–12 years and can be administered beginning at 9 years of age (16); girls and women aged 13–26 years who have not started or completed the vaccine series should receive the vaccine. The quadrivalent or 9-valent HPV vaccine is recommended routinely for boys aged 11–12 years; boys can be vaccinated beginning at 9 years of age (https://www.cdc.gov/vaccines/hcp/acip-recs/index.html). Boys and men aged 13–21 years who have not started or completed the vaccine series should receive the vaccine (16) (https://www.cdc.gov/vaccines/hcp/acip-recs/index.html). For previously unvaccinated, immunocompromised persons (including persons with HIV infection) and MSM, vaccination is recommended through age 26 years (16). In the United States, the vaccines are not licensed or recommended for use in men or women aged >26 years (16). HPV vaccines are not recommended for use in pregnant women. HPV vaccines can be administered regardless of history of anogenital warts, abnormal Pap/HPV tests, or anogenital precancer. Women who have received HPV vaccine should continue routine cervical cancer screening if they are aged ≥21 years. HPV vaccine is available for eligible children and adolescents aged <19 years through the Vaccines for Children (VFC) program (information available by calling CDC INFO [800–232–4636]). For uninsured persons aged 19–26 years, patient assistance programs are available from the vaccine manufacturers. Prelicensure and postlicensure safety evaluations have found the vaccine to be well tolerated (764) (https://www.cdc.gov/vaccinesafety/Vaccines/HPV/index.html). Impact-monitoring studies in the United States have demonstrated reductions of genital warts, as well as the HPV types contained within the quadrivalent vaccine (765,766). The current recommendations for HPV vaccination are available at https://www.cdc.gov/vaccines/hcp/acip-recs/index.html.

Settings that provide STD services should either administer the vaccine to eligible clients who have not started or completed the vaccine series or refer these persons to another facility equipped to provide the vaccine. Clinicians providing services to children, adolescents, and young adults should be knowledgeable about HPV and HPV vaccine (https://www.cdc.gov/vaccines/who/teens/for-hcp/hpv-resources.html). HPV vaccination has not been associated with initiation of sexual activity or sexual risk behaviors or perceptions about sexually transmitted infections (128).

Abstaining from sexual activity is the most reliable method for preventing genital HPV infection. Persons can decrease their chances of infection by practicing consistent and correct condom use and limiting their number of sex partners. Although these interventions might not fully protect against HPV, they can decrease the chances of HPV acquisition and transmission.

Diagnostic Considerations

HPV tests are available to detect oncogenic types of HPV infection and are used in the context of cervical cancer screening and management or follow-up of abnormal cervical cytology or histology (see Cervical Cancer, Screening Recommendations). These tests should not be used for male partners of women with HPV or women aged <25 years, for diagnosis of genital warts, or as a general STD test.

The application of 3%–5% acetic acid, which might cause affected areas to turn white, has been used by some providers to detect genital mucosa infected with HPV. The routine use of this procedure to detect mucosal changes attributed to HPV infection is not recommended because the results do not influence clinical management.

Treatment

Treatment is directed to the macroscopic (e.g., genital warts) or pathologic precancerous lesions caused by HPV. Subclinical genital HPV infection typically clears spontaneously; therefore, specific antiviral therapy is not recommended to eradicate HPV infection. Precancerous lesions are detected through cervical cancer screening (see Cervical Cancer, Screening Recommendations); HPV-related precancer should be managed based on existing guidance.

Counseling

Key Messages for Persons with HPV Infection

General

• Anogenital HPV infection is very common. It usually infects the anogenital area but can infect other areas including the mouth and throat. Most sexually active people get HPV at some time in their lives, although most never know it.
• Partners who have been together tend to share HPV, and it is not possible to determine which partner transmitted the original infection. Having HPV does not mean that a person or his/her partner is having sex outside the relationship.
• Most persons who acquire HPV clear the infection spontaneously and have no associated health problems. When the HPV infection does not clear, genital warts, precancers, and cancers of the cervix, anus, penis, vulva, vagina, head, and neck might develop.
• The types of HPV that cause genital warts are different from the types that can cause cancer.
• Many types of HPV are sexually transmitted through anogenital contact, mainly during vaginal and anal sex. HPV also might be transmitted during genital-to-genital contact without penetration and oral sex. In rare cases, a pregnant woman can transmit HPV to an infant during delivery.
• Having HPV does not make it harder for a woman to get pregnant or carry a pregnancy to term. However, some of the precancers or cancers that HPV can cause, and the treatments needed to treat them, might lower a woman’s ability to get pregnant or have an uncomplicated delivery. Treatments are available for the conditions caused by HPV, but not for the virus itself.
• No HPV test can determine which HPV infection will clear and which will progress. However, in certain circumstances, HPV tests can determine whether a woman is at increased risk for cervical cancer. These tests are not for detecting other HPV-related problems, nor are they useful in women aged<25 years or men of any age.

Prevention of HPV

• Two HPV vaccines can prevent diseases and cancers caused by HPV. The Cervarix and Gardasil vaccines protect against most cases of cervical cancer; Gardasil also protects against most genital warts. HPV vaccines are recommended routinely for boys and girls aged 11–12 years; either vaccine is recommended for girls/women, whereas only one vaccine (Gardasil) is recommended for boys/men (https://www.cdc.gov/vaccines/vpd-vac/hpv). These vaccines are safe and effective.
• Condoms used consistently and correctly can lower the chances of acquiring and transmitting HPV and developing HPV-related diseases (e.g., genital warts and cervical cancer). However, because HPV can infect areas not covered by a condom, condoms might not fully protect against HPV.
• Limiting number of sex partners can reduce the risk for HPV. However, even persons with only one lifetime sex partner can get HPV.

Abstaining from sexual activity is the most reliable method for preventing genital HPV infection. 

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