What is the herpes simplex virus?
Some people call it a cold sore, others a fever blister, but this annoying and often painful chronic condition is caused by the same virus: herpes simplex. About 50 percent to 80 percent of US adults are infected with this virus. Once infected, a person will have the herpes simplex virus for the rest of his/her life. When inactive, the virus lies dormant in a group of nerve cells. Some people never have any symptoms from the virus, others have periodic outbreaks of infections.