Human papillomavirus (HPV) vaccine

Human papillomavirus (HPV) vaccine

Author
Philip Castle, PhD, MPH
Section Editor
Martin S Hirsch, MD
Deputy Editor
Barbara H McGovern, MD

Disclosures

HPV VACCINE OVERVIEW — Human papillomavirus (HPV) is a virus that causes cervical cancer and genital warts. Persistent infection with certain types of HPV can lead to cancer of the cervix, which affects more than 10,000 American women every year. HPV can also cause cancers of the vulva, vagina, and anus, although these cancers are much less common than cervical cancer.

Two vaccines (Gardasil® and Cervarix®) are available to prevent infection with several types of HPV known to cause cervical cancer. It is hoped that these vaccines will significantly reduce the number of women who develop cervical cancer and pre-cancer.

This article discusses human papillomavirus and the human papillomavirus vaccine. Articles that discuss cervical cancer, cervical cancer screening (Pap smears), and genital warts are also available. (See “Patient information: Cervical cancer treatment; early stage cancer” and “Patient information: Cervical cancer screening” and “Patient information: Genital warts in women”.) An article that discusses vaccines recommended for adults is also available. (See “Patient information: Adult vaccines”.)

More detailed information about human papillomavirus vaccines is available by subscription. (See “Recommendations for the use of human papillomavirus vaccines”.)

WHAT IS HPV? — Human papillomavirus (HPV) is a virus that is spread by skin-to-skin contact, including sexual intercourse, oral sex, anal sex, or any other contact involving the genital area (eg, hand to genital contact). Condoms do not provide complete protection from HPV infection because condoms do not cover all exposed genital skin. People do not become infected with HPV by touching an object, such as a toilet seat.

The risk of HPV exposure increases with the number of sexual partners you have and the number of partners your partner has. It has been estimated that 75 to 80 percent of sexually active adults will acquire HPV infection before the age of 50. A majority of women and men become infected with HPV for the first time between ages 15 and 25 years. Most people who are infected with HPV have no signs or symptoms and clear the infection within two years, often without treatment.

In 10 to 20 percent of people, however, the infection persists. In this situation, there is a greater chance of developing cervical pre-cancer and then cancer. However, it usually takes at least 20 years for HPV infection to cause cervical cancer. Thus, regular testing is important in detecting cervical abnormalities early, before cancer develops. (See “Patient information: Cervical cancer screening”.)

Over 100 different types of HPV have been identified; more than 40 of these are known to infect the cervix and approximately 15 are known to cause cervical cancer. Researchers have labeled the HPV types as being high or low risk for causing cervical cancer.

HPV types 6 and 11 can cause about 90 percent of genital warts. These types are low-risk because they do not cause cervical cancer. (See “Patient information: Genital warts in women”.)
Types 16 and 18 are the high-risk types that cause most (about 70 percent) cases of cervical cancer. HPV types 45 and 31 are also high-risk types, causing about 5 to 10 percent of cervical cancers.
There are two HPV vaccines available. Talk to your healthcare provider to determine which vaccine is best for you.

One HPV vaccine (Gardasil®) helps to prevent infection with four HPV types (6, 11, 16, and 18)
The other vaccine (Cervarix®) prevents infection with HPV types 16 and 18, and it may offer some protection against HPV types 45 and 31.
HPV VACCINE TIMING AND DOSE — Gardasil® is given by injection and requires three doses; the first injection is followed by a second and third dose two and six months later, respectively.

Cervarix® is also given by injection and requires three doses, although the schedule is slightly different than with Gardasil; the first injection is followed by a second and third dose one and six months later, respectively.

It is not clear if the vaccine is effective if fewer than three doses are given. If you miss a dose, talk to your healthcare provider about how many more doses you need.

Who should be vaccinated? — In the United States, HPV vaccination is recommended for all girls and women who are between ages 9 and 26 years.

With both vaccines, you will have the greatest protection from HPV if you are vaccinated BEFORE becoming sexually active. The vaccine does not help to get rid of HPV infection after it has occurred. However, if you are less than 26 years old and you have been sexually active, had genital warts, a positive HPV test, or an abnormal Pap smear, you may still obtain some benefit from the HPV vaccine.

How long am I protected? — Scientists do not know exactly how long the vaccine protects against HPV infection. Clinical trials show that it provides protection for at least five years.

Do I still need a Pap smear? — You do not need to have a pelvic exam or test for cervical cancer (eg, Pap smear) before you have the HPV vaccine. Cervical cancer screening (Pap smear) is recommended, starting by age 21 or within three years of having sex for the first time.

However, getting the HPV vaccine does not mean that you can skip cervical cancer screening in the future, since the vaccine does not treat pre-existing infections. Other types of HPV, which are not prevented by the vaccine, can also cause cervical cancer. (See “Patient information: Cervical cancer screening”.)

HPV VACCINE SIDE EFFECTS AND PRECAUTIONS — The HPV vaccine may cause mild redness, tenderness, or swelling near the injection site. There is no thimerosal (a mercury derivative used as a preservative) in the HPV vaccine. There may be an increased risk of passing out or developing blood clots after an injection of Gardasil®. However, there are no known long-term side effects of the HPV vaccine.

The vaccine is not currently recommended during pregnancy, although there are no known risks to a fetus if the vaccine is given.

Despite recent concerns about the safety of the vaccine, most experts continue to believe that the benefits of the vaccine outweigh its risks [1].

DOES THE VACCINE REALLY WORK? — Results from vaccine studies show that the HPV vaccine is very effective in preventing HPV infections and cervical pre-cancers caused by HPV [2-5].

In the United States and elsewhere, the HPV vaccine is now available for boys and young men age 9 to 26 years. The benefits of the vaccine for men are that it might reduce the risk of developing genital warts and spreading HPV to sexual partners.

OTHER SEXUALLY TRANSMITTED INFECTIONS — The HPV vaccine is not perfect, meaning that some women will acquire an HPV infection despite having being vaccinated. In addition, the vaccine does not prevent other sexually transmitted infections (STIs), including HIV, chlamydia, and gonorrhea.

It is important to practice safer sex to reduce the risk of all STIs. This includes using a male or female condom with every sexual act. (See “Patient information: Barrier methods of birth control”.)

WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

 

Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient Level Information:

Patient information: Cervical cancer treatment; early stage cancer
Patient information: Cervical cancer screening
Patient information: Genital warts in women
Patient information: Adult vaccines
Patient information: Barrier methods of birth control

Professional Level Information:

Anal intraepithelial neoplasia: Diagnosis, screening, and treatment
Carcinoma of the penis: Epidemiology, risk factors, and clinical presentation
Cervical intraepithelial neoplasia: Definition, incidence, and pathogenesis
Cervical intraepithelial neoplasia: Management
Clinical trials of human papillomavirus vaccines
Condylomata acuminata (anogenital warts)
Epidemiology of human papillomavirus infections
Invasive cervical cancer: Epidemiology, risk factors, clinical manifestations, and diagnosis
Recommendations for the use of human papillomavirus vaccines
Treatment of vulvar and vaginal warts
Virology of human papillomavirus infections and the link to cancer

The following organizations also provide reliable health information.

National Cancer Institute
(www.nci.nih.gov/cancertopics/factsheet/prevention/HPV-vaccine)

National HPV and Cervical Cancer Public Education Campaign
Telephone: 1-866-280-6605
(www.cervicalcancercampaign.org)

Center for Disease Control and Prevention
(www.cdc.gov/std/hpv/STDFact-HPV-vaccine-young-women.htm)

American Social Health Association
(www.ashastd.org/)

REFERENCES
www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/ucm179549.htm (Accessed on October 14, 2011).
Garland SM, Hernandez-Avila M, Wheeler CM, et al. Quadrivalent vaccine against human papillomavirus to prevent anogenital diseases. N Engl J Med 2007; 356:1928.
Villa LL, Costa RL, Petta CA, et al. High sustained efficacy of a prophylactic quadrivalent human papillomavirus types 6/11/16/18 L1 virus-like particle vaccine through 5 years of follow-up. Br J Cancer 2006; 95:1459.
Paavonen J, Jenkins D, Bosch FX, et al. Efficacy of a prophylactic adjuvanted bivalent L1 virus-like-particle vaccine against infection with human papillomavirus types 16 and 18 in young women: an interim analysis of a phase III double-blind, randomised controlled trial. Lancet 2007; 369:2161.
Olsson SE, Villa LL, Costa RL, et al. Induction of immune memory following administration of a prophylactic quadrivalent human papillomavirus (HPV) types 6/11/16/18 L1 virus-like particle (VLP) vaccine. Vaccine 2007; 25:4931.
Joura EA, Leodolter S, Hernandez-Avila M, et al. Efficacy of a quadrivalent prophylactic human papillomavirus (types 6, 11, 16, and 18) L1 virus-like-particle vaccine against high-grade vulval and vaginal lesions: a combined analysis of three randomised clinical trials. Lancet 2007; 369:1693.