Human Papillomavirus

Updated: January 4, 2012

Table of Contents

    Understanding the Disease

    Human papillomaviruses (HPVs) are a group of more than 120 different viruses. Some are acquired by intimate sexual contact.

    Approximately 40 HPV types are primarily sexually transmitted from person to person (for example, genital-genital contact, oral-genital contact and sexual intercourse), infecting the oral, anal or genital areas of both men and women. Genital HPV infections are very common: acquisition shortly after starting to have sex occurs commonly. One quarter of females 15-19 years of age and 45% of those who are 20-24 years of age have evidence of genital HPV infection. By 50 years of age, 70-80% of women and a similar percentage of men will have acquired genital HPV infection.

    Most HPV infections cause no symptoms and are cleared by the immune system within a few weeks or months. Thus, the vast majority of people recover from HPV infection uneventfully. However, some people develop persistent HPV infection, some of which can lead to genital warts and others can cause cancers:

    • Types 16 and 18 and others, known collectively as “high-risk” HPV types, may cause abnormal Pap tests and cervical cancer in women. Together types 16 and 18 cause approximately 70% of the cases of cervical cancer in the United States. Although there are a number of other risk factors for cervical cancer, being infected with a “high-risk” type HPV appears to be necessary to develop cervical cancer.
    • In both men and women, “high-risk” HPV infections are also thought to cause 85% of anal cancers, 50% of other anogenital cancers, 20% of cancers of the throat and mouth and 10% of cancers of the larynx (voice box) and esophagus. Data from cancer registries in the United States have shown increasing incidences of oropharyngeal (1% per year) and anal (3% per year) cancers.
    • HPV types 6 and 11 may cause genital warts. These two types of HPV are responsible for more than 90% of genital warts. These types may also spread from mother to infant during pregnancy or delivery and rarely can cause warts in the upper respiratory tract (throat, larynx) of the child.

    Available Vaccines

    Product: Gardasil (HPV4)
    Manufacturer: Merck
    Year Licensed: 2006

    Product: Cervarix (HPV2)
    Manufacturer: GlaxoSmithKline
    Year Licensed: 2009

    History of the Vaccine

    A Quadrivalent Human Papillomavirus (Types 6, 11, 16, 18) recombinant vaccine (HPV4) was licensed for use in females by the Food and Drug Administration in 2006 and a bivalent vaccine (Types 16 & 18) (HPV2) in 2009. In 2009, HPV4 was also licensed for the prevention of warts in males and, in 2010, for the prevention of anal cancers in both males and females. Both vaccines are effective at preventing HPV infections of the specific types contained in the vaccines and, therefore, prevent precancers and cancers due to HPV 16 and 18. HPV4 has also been shown to prevent genital warts due to HPV 6 & 11 in both males and females.

    Who Should and Should Not Receive the Vaccine

    Who should receive the HPV vaccine?

    • Routine vaccination with HPV4 is recommended for all children 11-12 years of age as a 3-dose series. The vaccination series can be started in children as young as 9 years of age. Catch-up HPV4 vaccination is also recommended for males 13 through 21 years of age and for females 13-26 years of age who have not been vaccinated previously or who have not completed the full vaccine series, whether or not they have had sexual intercourse or previous evidence of HPV infection.
    • Men who sex with men should be immunized with HPV4 through 26 years of age.
    • Males 22 years through 26 years of age and women 27 through 45 years of age may also be vaccinated.

    Women who are breastfeeding can receive the HPV vaccine. Also, immunocompromised persons (from disease or medication) can receive the vaccine; however, the immune response to vaccination and vaccine effectiveness might be less than in persons who are not immunocompromised.


    Who should not receive the HPV vaccine?

    • Data on HPV4 vaccination during pregnancy is limited. However, there is no evidence of risk to the fetus when a pregnant woman is inadvertently vaccinated; the manufacturer is maintaining a registry of pregnancy outcomes for this circumstance.
    • People with a history of immediate hypersensitivity to yeast or to any vaccine component should not receive the vaccine.
    • People with minor illnesses (for example, diarrhea or mild upper respiratory tract infections, with or without fever) can receive the vaccine. However, those with moderate or severe acute illnesses should be deferred until after the illness improves.

    Dose Schedule

    Each dose of HPV4 vaccine is 0.5 mL, administered intramuscularly. It should be administered in a three dose schedule. The second dose should be administered 1-2 months after the first dose and the third dose should be administered 6 months (at least 24 weeks) after the first dose.

    HPV4 vaccine can be administered at the same visit when other age appropriate vaccines are provided, such as Tdap and MCV4.

    Effectiveness of the Vaccine

    The efficacy of both HPV vaccines for preventing persistent infection, cervical precancer, and cervical cancer have been studied extensively in women 16-26 years of age. In women who previously had not been exposed to the HPV types in the vaccine, the vaccines were highly efficacious as well effective in preventing vulvar and vaginal precancers. HPV4 has also been shown to be highly effective at prevention of genital warts and other types of precancerous lesions in both men and women caused by  the HPV types in the vaccines.

    HPV vaccines do not prevent chronic HPV infection or the development of disease caused by HPV in persons already infected with one of the HPV types in the vaccine.

    How long the vaccines will protect those who have been immunized is not yet known although waning serologic immunity does not seem to indicate a loss of immunity.

    Known Side Effects

    The HPV vaccines have been tested in large numbers of  vaccinees in many countries around the world, including the United States. These studies found that the HPV vaccines were safe and caused no serious side effects. Vaccine recipients experienced pain, swelling and redness at the injection sites, however. Vaccine Safety Datalink studies from more than 600,000 HPV4 doses administered showed no increased risk for Guillan-Barré syndrome, stroke, venous thomboembolism, appendicitis,seizure, fainting, and allergic reactions, including anaphylaxis.

    However, immunizations in general in preteens and teenage patients, especially females, has been associated with fainting, suggesting that patients should remain seated for a few minutes after vaccine administration.

    The HPV vaccine does not contain thimerosal.

    Related Issues

    Because these HPV4 will only prevent infection with the two types of HPV that cause most cases of HPV-associated cancers and the two types that cause most cases of genital warts, the vaccine will not eliminate HPV-associated cancers nor eliminate genital warts. As a consequence, routine Pap screening and treatment programs for cervical cancer will remain important preventive medical interventions.

    These vaccines are preventive and have no effect on pre-existing infection with these HPV types. Because HPVs are spread by intimate contact, some experts consider that universal immunization of children at 11-12 years of age (both boys and girls) may provide a greatly reduced disease burden caused by HPV 16 and 18 as a result of community immunity.

    Key References and Sources of Additional Information

    CDC Information