Overview of HPV Vaccination
Human papillomavirus, or HPV, is a collective term for more than 150 types of viruses, some of which lead to abnormal growths or cell changes. Warts (e.g., plantar warts, warts on the tongue or tonsils), also called verrucae, are benign growths on the skin or mucous membranes that are caused by HPV.
Human papillomaviruses are spread through contact with the skin or mucous membranes (e.g., lining of the mouth or genitourinary tract). According to the National Cancer Institute (NCI), about 40 types of HPV the virus are easily spread through direct skin-to-skin contact during vaginal, anal, and oral sex. Genital HPV infection, which attacks skin and mucous membranes around the penis, vagina, cervix, vulva, anus, and rectum, can cause genital warts and increase the risk for cervical cancer and other types of cancer.
The NCI reports that more than 50 percent of cases of cancer of the oropharynx (middle part of the throat including the soft palate, the base of the tongue, and the tonsils) in the United States are linked to HPV-16. HPV-associated oropharyngeal cancer incidence has increased in recent years, especially among men. By 2020, it's estimated that HPV will cause more oropharyngeal cancers than cervical cancers in the United States.
According to the Centers for Disease Control and Prevention (CDC), approximately 50 percent of sexually active adults will eventually contract HPV infection. In the United States, about 20 million people are currently infected with the virus and more than 6 million new cases are diagnosed each year.
In about 90 percent of cases, antibodies produced by the body's immune system are able to destroy the virus and fight off HPV infection within 2 years. In some cases, HPV infection does not completely clear up, even after many years. When this occurs, it is possible to continue to spread the virus to others.
Health care providers classify HPV as low risk and high risk. Low-risk HPV infections usually cause genital warts. High-risk infections are more likely to develop into cancer (e.g., cervical cancer), especially if the infection persists for 2 years or longer.
In June 2006, the U.S. Food and Drug Administration (FDA) approved the vaccine Gardasil®, for use in girls and young women between the ages of 9 and 26. This vaccine does not treat HPV infection, but it can help prevent types of HPV that cause genital warts and cervical cancer, if it is given before exposure to these viruses.
In February 2012, the CDC's Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) recommended HPV vaccination in boys ages 11 to 12 and catch-up immunizations for teenage boys. Previously, in October 2009, the FDA approved Gardasil for use in boys and men between the ages of 9 and 26 to prevent genital warts caused by HPV types 6 and 11. Three injections of the vaccine are administered over a 6-month period. Side effects include headache, fever, and injection site reactions (e.g., pain, itching, redness, swelling, bruising).
Brady M, et al "Recommended childhood and adolescent immunization schedules -- United States, 2012" Pediatrics 2012; 129: 385-386.
CDC. HPV Vaccine Information For Young Women - Fact Sheet. Available at http://www.cdc.gov/std/hpv/STDFact-HPV-vaccine-young-women.htm Accessed on February 7, 2012.
CDC. Recommendations on the Use of Quadrivalent Human Papillomavirus Vaccine in Males — Advisory Committee on Immunization Practices (ACIP), 2011. Available at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6050a3.htm Accessed on February 6, 2012.