Sex with a person with hepatitis B does not necessarily lead to infection. The source of hepatitis B is mainly acute and chronic hepatitis B patients and virus carriers. Acute patients are infectious at the end of the incubation period and in the acute stage, chronic patients and virus carriers have the greatest significance as the source of infection, and their infectiousness is directly proportional to the viral load in body fluids. With the popularization of hepatitis B vaccination, spouses of hepatitis B patients who have obtained more than the effective concentration of hepatitis B surface antibodies through hepatitis B vaccination will not be infected if they have sex with hepatitis B patients. In addition, if you have sex with hepatitis B patients, you can also avoid hepatitis B virus infection by wearing condom and other ways to protect yourself and avoid contact with body fluids. Therefore, when having sex with a person with hepatitis B, as long as you take good protective measures and get vaccinated in time to ensure that your body is positive for the surface antibody of hepatitis B virus, you can greatly reduce the risk of infection.