Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The human papillomaviruses are a group of 150 related viruses capable of infecting humans. Human papillomavirus infections are the most common sexually transmitted infections in the United States - more than half of sexually active people are infected with one or more HPV types at some point in their lives. Recent research indicates that, at any point in time, 42.5 percent of women have genital HPV infections, whereas less than 7 percent of adults have oral HPV infections. While the majority of the known types of HPV cause no symptoms in most people, some types can cause warts, while others can – in a minority of cases – lead to cancers of the cervix, vulva, vagina, penis, oropharynx and anus. Learn more about human papillomaviruses, their life-cycle and transmission, as well as their cures and vaccines in the following pages.