Does the hepatitis B vaccine lose its effectiveness?

Under normal circumstances, the protective effect of the hepatitis B vaccine may gradually diminish over time. For most people, the immunity remains effective long-term after successful immunization; however, protection may wane when antibody levels become insufficient. If concerned, it is advisable to consult a healthcare provider in advance. Detailed analysis is as follows:

For individuals who have completed the full course of hepatitis B vaccination according to standard protocols and developed sufficient protective antibodies (antibody titer ≥10 mIU/mL), the vaccine typically provides protection for at least 30 years in those with normal immune function. Even if antibody titers decline over time, immune memory cells within the body can rapidly activate upon exposure to the virus, producing antibodies to prevent infection. In such cases, vaccine effectiveness generally does not fail.

If an individual fails to develop adequate antibodies after vaccination, or if antibody titers remain persistently below 10 mIU/mL, the vaccine may lose its protective effect. Factors such as impaired immune function, incomplete or irregular vaccination schedules, or prolonged exposure to the hepatitis B virus environment may accelerate the decline in antibody levels, increasing the risk of infection. These situations require vigilance regarding potential vaccine "failure."

After receiving the hepatitis B vaccine, individuals are advised to regularly monitor their antibody titers. A booster dose should be administered promptly if antibody levels fall below 10 mIU/mL. High-risk individuals should undergo retesting every 3–5 years to ensure sustained protection and reduce the risk of infection.