While no prevention method short of abstinence is % effective, using a latex condom offers some protection. Your partner should tell you when symptoms flare up, which is when the virus is most contagious. Avoid sex when your partner has symptoms. Always use condoms and dental dams during oral, anal, and vaginal sex. Talk with your doctor about taking herpes medication every day, which can lower your chances of spreading herpes. Don't have sex during a herpes outbreak, even with a condom. There may be sores on places the condom doesn't cover.