Hsv-1also called oral herpes, hsv-1 can easily be passed on through kissing. It's also common: 67 percent of people under 50 have the virus in their bodies.

Cytomegalovirus (cmv) is a viral infection that can be passed on through contact with saliva that contains the virus. It can also be transmitted through the following fluids that contain cmv:β€’urine syphilis, a bacterial infection, isn't typically transmitted by kissing. It's more commonly spread through oral, anal, or genital sex. But syphilis can cause sores in your mouth that can transmit the bacteria to someone else.