Human papillomavirus (HPV) is a sexually transmitted virus that can affect men and women. It is the most common sexually transmitted disease — currently, more than 20 million Americans are infected with HPV and another 6 million become newly infected each year. Most of the time, HPV is harmless and goes away on its own. But it can cause genital warts and several types of cancer, including cervical and head and neck cancers. That’s why it’s important to protect yourself against HPV transmission with these eight strategies.