Not many of us know much about human papillomavirus (HPV), despite the alarming fact that one in four men carry a strain of the virus that’s been proven to cause cancer. By comparison, only one in five women carry the virus, even though HPV prevention awareness among women has been more robust. This new statistic, attained from The National Center for Health Statistics, was pulled from several large national health surveys that includes data from HPV tests from 2011 through 2014. Those results have also revealed that nearly half of men and 40 percent of women carry some kind of genital HPV.

Overall, 42.5 percent of adults ages 18 to 59 have genital HPV. Asian adults had the lowest rates of infection, while African Americans had the highest. In most cases, men had higher rates of both oral and genital HPV than women, the former of which is spread by oral sex.

“Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States,” NCHS wrote, adding that some forms of the virus can cause genital warts, but these particular strains are often considered low-risk as they hava much lesser chances of causing cancer. High-risk strains cause cancer in different areas of the body including the cervix and vagina in women, the penis and anus in men, and then mouth and throat in both genders.

Currently, 70 percent of all head and neck cancers are caused by HPV and by 2020, researchers predict that these cases will surpass cervical as the most common case of HPV-related cancer. As it currently stands, there are two FDA-approved vaccines, Cervarix and Gardasil, that prevent infection by the cancer-causing strains, the latter of which also combats strains that cause warts. A newer form of Gardasil, approved earlier this year, adds five more high-risk HPV strains to its coverage, but even so, that’s still just a fraction of the 40 documented types, according to Time.

Vaccinations against HPV first became available in 2006 and were originally aimed at protecting kids before they become sexually active. In 2009, health organizations included boys in that recommendation. In the six years following the recommendation, infection rates dropped among teens by 64 percent.

Despite HPV being the most common sexually transmitted disease among Americans, only 30 to 40 percent of sexually active teens have received the three-dose shot. Worse than that, only 10 percent of men have.