Should I get the HPV vaccine?

More than 100 strains of human papillomavirus (HPV) are known to exist, and more than 30 of them are sexually transmitted. HPV infection causes diseases ranging from common warts to invasive cervical cancer.

Sexually transmitted HPV is classified as high risk or low risk, depending on the oncogenic potential of the strain. For example, HPV-6 and HPV-11 are primarily responsible for 90% of all cases of condyloma acuminatum. These strains are classified as low risk because they rarely cause a carcinoma. On the other hand, HPV strains 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, and 69 have a significantly higher oncogenic potential. HPV-16 and HPV-18 together account for approximately 70% of all cases of cervical cancer.

Most sexually transmitted strains do not cause symptoms and spontaneously resolve without significant consequences. ¹ In approximately 90% of infected patients, the immune system either clears the virus or causes it to remain dormant.² However, having multiple sexual partners, smoking, and higher parity increase the risk that precancerous or malignant lesions will develop following exposure to a high-risk oncogenic strain.³

The FDA licensed the quadrivalent HPV recombinant vaccine in June 2006. It is approved for the prevention of all diseases caused by HPV types 6, 11, 16, and 18 and is approved for use in females aged 9 to 26 years. The vaccine consists of a series of three IM injections given at 0, 2, and 6 months.⁴

The complete series should be administered prior to the initiation of sexual intercourse for the vaccine to provide maximum protection. However, because a woman is rarely infected with all four of these strains, all women who are in this age group and are likely to acquire an HPV infection can obtain at least partial protection. No prior testing of HPV status needs to be done before initiating the series.⁴

The vaccine has been administered to more than 11,000 females to date without any serious adverse reactions. The most common side effect reported was pain at the injection site.⁴ In HPV-naive females, the vaccine is almost 100% effective in preventing precancerous and cancerous lesions of the cervix, vagina, and vulva and condyloma acuminatum.⁴ Whether a booster dose will be needed is not known; to date, immunity has persisted for 5 years.4 The vaccine is not recommended for pregnant women.⁴

The CDC's Advisory Committee on Immunization Practices (ACIP) recommends including this new vaccine among the routine immunizations for all girls aged 11 to 12 years.⁵ ACIP also recommends vaccinating all
females aged 9 to 26 years.⁵ The American Cancer Society (ACS) recommends vaccinating all girls aged 11 to 12 years and all girls aged 13 to 18 years who have not been previously vaccinated.6 The ACS guidelines also state that the vaccine can be administered to girls as young as 9 years; however, the ACS finds current data to be insufficient for recommending the vaccine to women aged 19 to 26 years.⁶ The American College of Obstetricians and Gynecologists essentially recommends administering the vaccine to all females aged 9 to 26 years who have not been previously vaccinated.⁷

The HPV vaccine costs $120 per dose, $360 for the series.⁸ Once the vaccine has the approval of the full CDC and the ACIP recommendation is published in MMWR Morbidity and Mortality Weekly Report, it will be eligible
for reimbursement under the Vaccines for Children Program.

Studies currently underway are looking at the vaccine's effectiveness in older women and men, as well as at its effectiveness as a secondary preventive measure for cervical cancer in the female partners of infected men.⁵ The results of these studies will not be available for at least 2 years. Another bivalent vaccine effective against HPV-16 and HPV-18 is in the final stages of human clinical trials.⁵ JAAPA

Pam Scott is the owner of Physician Assistant Medical Services (P.A.M.S.) in Williamsburg, West Virginia, a past president of the AAPA, and president of the Society for the Preservation of PA History. The author has indicated no relationships to disclose relating to the content of this article,

1. Munoz N, Bosch FX, de Sanjose S, et al. Epidemiologic classification of human papillomavirus types associated with cervical cancer. N Engl J Med. 2003;348(6):518-527.

2. Ho GY, Bierman R, Beardsley L, et al. Natural history of cervicovaginal papillomavirus infection in young women. N Engl J Med. 1998;338(7):423-428.

3. Castle PE, Wacholder S, Lorincz AT, et al. A prospective study of high-grade cervical neoplasia risk among human papillomavirus-infected women. J Natl Cancer Inst. 2002;94(18):1406-1414.

4. HPV and HPV vaccine—information for healthcare providers.
Centers for Disease Control and Prevention Web site.
Available at: http://www.cdc.gov/std/hpv/STDFact-HPVvaccine-
hcp.htm. Accessed April 11, 2007.

5. CDC's advisory committee recommends human papillomavirus virus vaccination [press release]. Atlanta, Ga: Centers for Disease Control and Prevention; June 29, 2006. Available at: http://www.cdc.gov/od/oc/media/pressrel/r060629.htm. Accessed April 11, 2007.

6. Saslow D, Castle PE, Cox JT, et al. American Cancer Society guideline for human papillomavirus (HPV) vaccine use to prevent cervical cancer and its precursors. CA Cancer J Clin. 2007;57(1):7-28.

7. ACOG News Release. ACOG releases revised recommendations for women's health screenings and care. Available at: http://www.acog.org/from_home/publications/press_releases/nr12-01-06-2.cfm. Accesssed April 10, 2007.

8. HPV questions and answers. Centers for Disease Control and Prevention Web site. Available at: http://www.cdc.gov/std/hpv/STDFact-HPV-vaccine.htm. Accessed April 11, 2007.