After infection with the hepatitis B virus, the surface antigen of hepatitis B can usually be detected in the serum in about 2-8 weeks, thus providing a clear diagnosis. It is important to note that the hepatitis B virus generally has an incubation period of about 90 days, during which it is often asymptomatic and not easily detectable. The pathogenesis (i.e., the time to clinical symptoms) varies with the immune response of each person. Approximately 5-10% of adults infected with hepatitis B virus will develop chronic hepatitis B or become carriers. More than 80% of children who become infected will become carriers. Therefore, people who suspect that they have been infected with the hepatitis B virus through contact with a hepatitis B patient can have their serum checked for the hepatitis B virus in 2 weeks or a month later. In addition, it is recommended that people who are in close contact with high-risk groups and who are antibody-negative after checking the five hepatitis B items should be vaccinated against hepatitis B to effectively avoid being infected by the hepatitis B virus.