Studies indicate that immunologic memory remains intact for at least 30 years and confers protection against clinical illness and chronic HBV infection, even though anti-HBs levels that once measured adequate might become low or decline below detectable levels. If exposed to HBV, people whose immune systems are competent will mount an anamnestic response and develop protective anti-HBs. Studies are on-going to assess whether booster doses of HepB will be needed in the future. CDC
Who should be tested for anti-HBs after vaccination?
Serologic testing for immunity is not necessary or recommended after routine vaccination of infants, children, or adults. Testing for anti-HBs after vaccination is recommended for the following groups whose subsequent clinical management depends on knowledge of their immune status:•Infants born to HBsAg-positive women and infants born to women whose HBsAg status remains unknown (for example, infants surrendered shortly after birth); postvaccination serologic testing should consist of testing for anti-HBs and HBsAg•Healthcare professionals and public safety workers at risk for blood or body fluid exposure•Hemodialysis patients (and other persons who might require outpatient hemodialysis), HIV-infected persons, and other immunocompromised persons (such as hematopoietic stem-cell transplant recipients or persons receiving chemotherapy), to determine the need for revaccination and the type of follow-up testing, and•Sex partners of HBsAg-positive persons, to determine if they have not achieved immunity and will need revaccination and to continue to use other methods of protection against HBV infection