Human papillomavirus (“HPV”) is a group of viruses that is extremely common worldwide. Some types of HPV can cause health problems, ranging from benign issues like skin warts to life-threatening conditions including anal cancer.
HPV is the most common sexually transmitted infection in the U.S. In fact, it is so common that nearly all sexually active men and women get it at some point in their lives. In the U.S., an estimated 79 million persons are currently infected with HPV and there are 14 million new infections each year. In the majority of cases, HPV infections clear spontaneously and most people never realize they were infected. However, some infections persist, cause symptoms, and reactivate years after initial exposure.
There are more than 150 types of HPV, of which at least 13 are considered cancer causing. Anal and cervical cancers share some of these cancer-causing HPV types. Importantly, HPV types 16 and 18 likely cause 79% of anal cancers.
HPV is spread through skin-to-skin contact and can cause normal cells on infected skin to turn abnormal. Different HPV types have a propensity to infect different body sites. For example, many HPV types have a tendency to infect the skin, causing skin warts on the hand and feet. Other HPV types, such as 6, 11, 16, and 18, specifically target mucus membranes and skin in genital areas including the penis, scrotum, anal canal, perianal regions, the vaginal entrance, vulva, and cervix. These types are primarily transmitted by genital contact. HPV types 6 and 11 can lead to genital warts while HPV types 16 and 18 can lead to abnormal cell proliferation and cancer.