The human papillomavirus, or HPV, is the most common sexually transmitted infection, or STI, in the United States, with an estimated 79 million Americans currently infected and 14 million newly infected persons per year, according to the U.S. Centers for Disease Control and Prevention. There are more than 40 types of HPV that can affect the genitals, mouth and throat and can lead to genital warts or many types of cancers, including cervical. HPV is passed between partners through skin to skin contact, and nearly all sexually active people contract HPV at some point in their lives.

Many times, the infected person does not experience any symptoms of the HPV infection but can continue to transmit the virus to a sexual partner. Additionally, in up to 90 percent of cases, the virus goes away on its own within two years, according to the CDC. When the virus stays, HPV can cause normal cells to become abnormal, leading to warts or cancer.

Until recently the main ways to prevent HPV infection were condom use and limiting the number of sex partners. With the introduction of the HPV vaccine, a safe, effective method to prevent infections with the most common types of HPV that cause infection and cancer is available. Vaccination is most effective before people become sexually active, so the CDC recommends HPV vaccines for all 11- and 12-year-olds. Gardisil® (vaccine for males and females that is active against four types of HPV) and Cervarix® (vaccine for females only active against two types of HPV) can be administered up to the age of 26. Both vaccines are administered in a three-shot series. The vaccine won't treat an existing HPV infection.

After the introduction of the vaccine in 2007, studies conducted in Australia and the United States all identified a decrease in genital warts as a result of HPV in both males and females under the age of 25. Similar decreases among the Army active-duty component beginning in 2007 were reported in a recent Medical Surveillance Monthly Report, or MSMR. The MSMR reported 163 new cases of HPV per 10,000 person-years from 2000--2012. Rates observed among women were twice as high as those among men. Rates for both males and females decreased with age, dropping substantially by age 25. By comparison, the rate of chlamydia for the same population and time period was 148 and for gonorrhea was 37.

While there is no test to determine one's overall HPV status, the PAP test is used to screen for cervical cancer in females beginning at the age of 21. In females over the age of 30, an HPV test can be performed along with the PAP test. There is no HPV test available at this time for males, nor is there a test to identify HPV in the mouth or throat.

Consult with your primary-care provider if you have any concerns about HPV or HPV vaccination, or to begin the vaccine series.