Vaccines
Human Papillomavirus
Updated: March 31, 2010
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 genital 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 genital 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.
- 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 by the Food and Drug Administration in 2006 and a bivalent vaccine (Types 16 & 18) (HPV2) in 2009. Both vaccines are effective at preventing HPV infections of the specific types contained in the vaccines and, therefore, prevent cervical 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 against HPV is recommended for all girls 11-12 years of age. Both HPV4 and HPV2 protect against cervical cancers and precancers. The vaccination series can be started in girls as young as 9 years of age.
- Catch-up vaccination is recommended 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.
- HPV4 may be administered to males aged 9 through 18 years and to women 27-45 years of age.
Women who are breastfeeding can receive the HPV vaccine. Also, immunocompromised women (from disease or medication) can receive the vaccine. However, the immune response to vaccination and vaccine effectiveness might be less than in women who are not immunocompromised.
Who should not receive the HPV vaccine?
- Pregnant women should not receive this vaccine, since data on 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 HPV 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 administe 6 months (at least 24 weeks) after the first dose.
HPV vaccine can be administered at the same visit when other age appropriate vaccines are provided, such as Tdap, Td and MCV4.
Effectiveness of the Vaccine
The efficacy of both HPV vaccines for preventing persistent infection, cervical precancer, and cervical cancer have been studied 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 also was effective for the prevention of genital warts caused by the targeted HPV types.
If a girl or woman is already infected with one of the HPV types in the vaccine, the vaccines did not prevent infection or development of disease from that type.
Studies have shown that over 99% of study participants developed antibodies after vaccination; antibody titers (levels) were higher for young girls than for older females participating in the efficacy trials.
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 vaccine has been tested in over 11,000 women (9-26 years of age) 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.
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 vaccines will only prevent infection with the two types of HPV that cause most cases of cervical cancer and HPV4 will prevent the most common causes of genital warts, the vaccines will not eliminate this cancer nor eliminate genital warts. Therefore Pap screening and treatment programs for cervical cancer will still be important.
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) would be expected to provide a greatly reduced burden of HPV 16 and 18 by community immunity
For more information see HPV Immunization Issues.
Key References and Sources of Additional Information
- CDC. 2010. FDA Licensure of Quadrivalent Human Papillomavirus Vaccine (HPV4, Gardasil) for Use in Males and Guidance from the Advisory Committee on Immunization Practices (ACIP) MMWR 59(20);630-632.
- CDC. 2010. FDA Licensure of Bivalent Human Papillomavirus Vaccine (HPV2, Cervarix) for Use in Females and Updated HPV Vaccination Recommendations from the Advisory Committee on Immunization Practices (ACIP).
