Objective: To evaluate the long-term protection following hepatitis B vaccination and assess whether revaccination is necessary after 15 years for those who have an increased occupational risk of hepatitis B infection.
Design: Systematic literature review
Method: Medline was searched for English language publications from the period 2002-2008 concerning vaccination against the hepatitis B virus. We included follow-up studies in which the interval between vaccination and titre measurement was at least 4 years.
Results: The 22 articles included describe 30 studies. Post-vaccination titre measurement was performed in 10 studies. Four of these described a change from negative to positive testing for anti-hepatitis B core antigen (anti-HBc) (seroconversion) in 0.64% of the 1,880 subjects tested. In the 20 studies in which no post-vaccination titre measurement was carried out, seroconversion was observed for anti-HBc and for hepatitis B surface antigens (HBsAg) in 1.0% and 1.78% of the vaccinees, respectively. These studies were predominantly carried out in high-endemic regions, mostly in newborns of HBsAg positive mothers. Seroconversions were not accompanied by clinical signs or symptoms. In 6 studies there was a follow-up of more than 15 years; the maximum was 23 years. Seroconversions did not appear specifically after a long period of time but were observed independent of time after vaccination.
Conclusion: Seroconversions occur in < 1% of successfully vaccinated subjects and do not increase after a period of 15 years following vaccination. In all the 23 years of experience with hepatitis B vaccination, it seems to have provided protection. This also applies to those at increased risk. Revaccination after successful vaccination would therefore not seem to be necessary, even after a period of 15 years.