Kissing can transmit viruses. At present, there are many types of viral infections, including viral hepatitis, influenza virus infection, measles, chickenpox herpes zoster, mumps, rabies, AIDS, epidemic encephalitis B, poliomyelitis and so on. Different viruses have different transmission characteristics, so not all diseases caused by viral pathogens are transmitted through kissing. Generally speaking, the transmission of infectious diseases can be categorized into three ways: blood transmission, direct or indirect contact transmission, and vertical transmission. Currently, viruses that can be transmitted through kissing include influenza virus, coronavirus, and other respiratory viruses, etc. Especially when there are mouth ulcers or broken skin around the mouth, the risk of contracting various types of blood-borne viruses, such as Hepatitis B, HIV, Hepatitis E, and Herpes Simplex Virus, etc., will gradually increase. Therefore, kissing is also a risk of viral infection, and people with viral infections are advised to avoid kissing.