Hepatitis B can be transmitted sexually, through blood or body fluids. Hepatitis B infection does not have much to do with being an adult, and having antibodies and a good immune system reduces the likelihood of transmission. When adults are weak and have close contact with hepatitis B patients, the probability of hepatitis B infection increases. However, if adults pay attention to diet and hygiene and exercise, have good immunity and have been vaccinated against hepatitis B in the past, the probability of hepatitis B infection will be relatively lower. Moreover, in China, most adults are vaccinated against hepatitis B and most of them carry hepatitis B surface antibody, so the probability of hepatitis B infection will be greatly reduced, but we cannot rule out the possibility of hepatitis B infection in adults. Regular physical examination is recommended. If the surface antibody against hepatitis B is lower than 10mIU/ml, the resistance is reduced and hepatitis B vaccine needs to be injected again.