Herpes Simplex Virus (HSV) is a highly contagious virus that causes genital herpes and is primarily spread through sexual contact, including oral, vaginal, and anal sex. HSV is classified into two types: HSV-1 and HSV-2. A positive result for HSV-1 IgG indicates past exposure to the virus, meaning you have been previously infected with HSV-1. This test helps identify prior infection, even if there are no current symptoms.