The absence of antibodies to the hepatitis B vaccine may be related to genetic factors, the body’s immune function, and HBV abnormalities. In addition, the site of vaccination and the type of vaccine are also common factors that lead to the absence of antibodies after hepatitis B vaccination. 1. Genetic factors: If the patient is affected by genetic factors and has a specific immune mechanism, the immune response may be affected, resulting in the absence of antibodies to the hepatitis B vaccine. 2. Human immune function: if the patient’s immune function is not well developed, it may lead to hepatitis B vaccine not producing antibody after injection, or producing too little antibody, and insufficient T-cell function will lead to no antibody after hepatitis B vaccination. 3. HBV abnormality: if HBV has been mutated, the antigenicity of HBV will be weakened, and the phenomenon of having no antibody after hepatitis B vaccination will also occur. 4. Vaccination site and vaccine type: if there is deviation in the vaccination site, or due to the relationship between the batch of hepatitis B vaccine and the manufacturer, there may also be no antibody after taking hepatitis B vaccine. If there is no antibody after taking hepatitis B vaccine, it is recommended to consult the relevant vaccination department to clarify the cause and then take targeted treatment.