If someone has herpes but no sores, can it still be passed on to another person?

Yes. Even when no sores are present, the herpes is still active in the body and can spread to others.

If you or your partner has herpes, here's how to reduce the risk of spread:

• Use a condom every time you have sex (vaginal, oral, or anal). The herpes virus can live outside of the area that a condom covers, though, so a condom may not always prevent the spread.
• Avoid sex during outbreaks (herpes is much more likely to spread during outbreaks).
• Make sure the infected person takes antiviral medicine every day as prescribed by their health care provider.

The only way to completely prevent herpes and other STDs (sexually transmitted diseases) is to not have sex (oral, vaginal, or anal).