If someone has herpes but no sores, can it still be passed on to another person?
Yes. Herpes can be passed on even if a partner has no sores or other signs and symptoms of an outbreak. And if a partner has a herpes outbreak, it's even more likely to be spread.
Even when a person doesn't have visible sores, the only surefire way to protect against getting genital herpes is abstinence. People who do have sex must use a latex condom correctly every time they have any form of sexual intercourse (vaginal, oral, or anal sex). Girls receiving oral sex should have their partners use dental dams as protection.
If one partner has a herpes outbreak (a tingling feeling that indicates an outbreak or visible sores), avoid sex — even with a condom or — until all sores have healed.