Theoretically kissing is not contagious to hepatitis B. This is because the hepatitis B virus is unable to invade the body through normal skin and mucous membranes. However, it has been clinically found that there are indeed cases of hepatitis B transmission through kissing. Why is this? Let’s find out why below. Kissing is not categorized as one of the transmission routes of hepatitis B. Theoretically, kissing does not transmit hepatitis B, but why are there cases of hepatitis B transmission through kissing found in the clinic? Can kissing spread hepatitis B? Hepatitis B virus can be detected in the saliva of hepatitis B patients, but under normal circumstances of kissing, these viruses cannot penetrate the normal mucous membrane of the digestive tract and infect the human body. However, if there are visible or hidden wounds in the mouth of the other party during kissing, such as broken oral mucosa, bleeding gums, ulcers, etc., this can allow the hepatitis B virus to take advantage of the situation and cause hepatitis B transmission. Therefore, you should avoid kissing for a while when you encounter similar situations during kissing to avoid infection. On the other hand, whether hepatitis B is contagious when a hepatitis B patient kisses is related to the resistance of the uninfected party. If the other party has enough protective antibodies against hepatitis B, even if a small amount of hepatitis B virus invades the human body through the skin and mucous membranes, it will be eliminated by the body’s immune system, which greatly reduces the possibility of infection; if the other party’s immune system is very imperfect, after the invasion of the hepatitis B virus, the human body’s immune system can’t recognize the hepatitis B virus, which may lead to hepatitis B virus infection. It can be seen that there are many factors affecting whether hepatitis B can be transmitted through kissing. Of course, if you have been vaccinated against hepatitis B and have produced sufficient antibodies, you basically do not have to worry about the transmission of hepatitis B through kissing anymore.