HPV is the most common sexually transmitted infection, and an estimated 75-80 percent of sexually active adults will get some type of genital HPV in their lifetimes. It can be transmitted by vaginal, anal or oral sex. Often, it's completely harmless and goes away on its own, but some types of the infection can lead to cancer of the cervix, mouth and tongue, throat, anus, vulva, penis, and vagina. The HPV vaccine, which the CDC recommends for preteens of all genders aged 11 or 12, provides protection against all of these. According to the CDC, young adults up to age 27 can drastically lower their risk by getting the vaccine even after the recommended age. However, the new study found that only around 51 percent of eligible people are vaccinated.