A recessive infection is an infection in which a pathogen is cleared away because the immune system is strong and no clinical symptoms are present, while resistance to the disease is developed. Most immunocompetent people exhibit recessive infection after infection with viruses or bacteria, but only a minority of people get the disease. This is also the case with hepatitis B virus infection. When infected with the hepatitis B virus, the body’s immune system quickly produces antibodies (resistance) to remove the hepatitis B virus, and the body shows no symptoms of hepatitis B, no elevated transaminases, and no virus remains in the body for long periods of time; this condition is recessive infection with the hepatitis B virus. Most immunocompetent adults who are infected with the hepatitis B virus show recessive infection, so it is for this reason that most spouses of hepatitis B virus-infected people do not get hepatitis B but produce antibodies instead before the hepatitis B vaccine is available. Occult infection means that after infection, the pathogen is not cleared by the immune system and is latent in the body, but does not show clinical symptoms, such as most of us who are carriers of hepatitis B virus belong to this situation. Therefore, hepatitis B virus infection often has an insidious onset and rarely has obvious clinical symptoms. However, there is a special type of infection among hepatitis B virus infected people, which is called occult chronic hepatitis B by our Guidelines for the Prevention and Treatment of Chronic Hepatitis B. This condition belongs to a special type of infection of the hepatitis B virus. The hepatitis B virus often undergoes some mutations during the replication process. If mutations occur at the site of the manifestation antigen (HBsAg, the first of the five hepatitis B items), we cannot detect the surface antigen of the hepatitis B virus with the general test method of the five hepatitis B items, which shows a negative surface antigen (HBsAg) of the hepatitis B virus, but there is other evidence of hepatitis B virus infection in the body, such as HBV-DNA positive or e antigen positive. This condition can also manifest as long-term carriage of the virus or as chronic hepatitis with abnormal liver function, which can be diagnosed by testing for HBV DNA or e antigen. This variant of the hepatitis B virus can “escape” recognition by the body’s immune system, making the hepatitis B vaccination ineffective. Therefore, a mother with this variant of the virus in her body may have a baby with an ineffective hepatitis B vaccination and an insidious hepatitis B virus infection. However, this is a very rare occurrence and the hepatitis B mother should not be overly concerned. When the child does not produce antibodies from the hepatitis B vaccination, the first thing to do is to continue to strengthen the immunization against hepatitis B. There is no need to rush to have the child tested for HBV-DNA.