https://cont.jd.com/pccontent/1514782
How long does protection from hepatitis B vaccine last?
Studies indicate that immunologic memory remains intact for at least 30 years among healthy people who initiated hepatitis B vaccination at >6 months of age (21). The vaccine confers long-term protection against clinical illness and chronic hepatitis B virus infection. Cellular immunity appears to persist even though antibody levels might become low or decline below detectable levels (22). Among vaccinated cohorts who initiated hepatitis B vaccination at birth, long-term follow-up studies are ongoing to determine the duration of vaccine-induced immunity (21).