Herpes, an infection caused by the herpes simplex virus, is estimated to be present in 50 to 80 percent of the American adult population. 20 percent, over 50 million people, are infected with genital herpes, also caused by the herpes simplex virus, and the majority of these cases may be unaware they even have it. Studies show that more than 500,000 Americans are diagnosed with genital herpes each year, and the largest increase is occurring in young teens. Results of a nationally representative study show that genital herpes infection is common in the United States. Nationwide, at least 45 million people ages 12 and older, or one out of five adolescents and adults, have had genital HSV infection. Between the late 1970s and the early 1990s, the number of Americans with genital herpes infection increased 30 percent! Herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2). Most genital herpes is caused by HSV-2. Most individuals have no or only minimal signs or symptoms from HSV-1 or HSV-2 infection. When signs do occur, they typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur. Typically, another outbreak can appear weeks or months after the first, but it almost always is less severe and shorter than the first outbreak. Although the infection can stay in the body indefinitely, the number of outbreaks tends to decrease over a period of years. Genital HSV-2 infection is more common in women (approximately one out of four women) than in men (almost one out of five). This may be due to male-to-female transmissions being more likely than female-to-male transmission. Living with genital herpes can be a hassle. When you have a herpes outbreak, it can feel like it takes days out of your life. And, you have questions about spreading genital herpes to a partner. Herpes symptoms can come and go, but the virus stays in the nerve cells of your body even after all signs of the infection have gone away. In most people, the virus becomes active from time to time, creating an outbreak. Some people have herpes virus outbreaks only once or twice. Other people have many outbreaks of herpes each year. Scientists don't know what causes the virus to become active, but the number of outbreaks a person has tends to go down over a period of years. Some women say the virus comes back when they are sick, under stress, out in the sun, or during their period. There is no cure for herpes to date. Supporting your immune system should be your first goal. A weakened immune system is more prone to outbreaks.