Question:

Can STIs be transmitted by contact with saliva or inanimate objects?

Answered by Sara Bares, MD, infectious diseases specialist:

While most sexually transmitted infections are transmitted through blood, vaginal secretions and semen, there are some that can also be contracted via contact with saliva and the mucous membranes in the mouth. For example, herpes simplex virus (the most common cause of cold sores), can be transmitted via kissing or oral to oral contact as well as by oral to genital and genital to genital contact. Gonorrhea, and less commonly, chlamydia, are also present in saliva and can be spread via kissing or oral to oral contact, as well as oral to genital and genital to genital contact. Importantly, all of these organisms can cause asymptomatic infection so they can spread before the person is aware they are infected. Syphilis is less likely to spread via saliva but the bacteria that causes syphilis can be present in oral sores and can thus be transmitted via kissing.

HIV is an STI that is not transmitted through saliva, only blood and genital fluid. HIV cannot be easily transmitted via kissing or via oral sex unless there is blood present in the saliva.

It is extremely unlikely that you would contract an STI when exposed to saliva from an inanimate object. In most cases, an STI present in saliva is inactivated once it is exposed to air. However, genital fluids and blood may harbor sexually transmitted bacteria and viruses that survive for longer periods of time in the air and would thus represent a higher risk of being transmitted via inanimate objects. It is therefore a good idea to thoroughly wash and disinfect sex toys after use.