Ten-year serological follow up of hepatitis B vaccine recipients.

AIM: To determine long-term persistence of antibodies to hepatitis B surface antigen (anti-HBs) after vaccination against hepatitis B. METHODS: Thirty-four laboratory workers received hepatitis B vaccine in 1989 in a 0-1-6 month vaccination schedule. Group A (n = 16) received a booster at 3 years after vaccination whereas Group B (n = 18) did not. Anti-HBs was quantitated at 1 month and 1, 2, 3, 5, 6 and 8 years post-vaccination. RESULTS: At eight-year follow up, 10 of 15 subjects in Group A and 3 of 16 in Group B had protective levels of anti-HBs; in addition, two and four subjects, respectively, had detectable anti-HBs though below protective levels. At ten years, 9/15 and 3/16 were anti-HBs positive in Groups A and B, respectively. One subject in each group had rise in anti-HBs titer at 6-year follow up but both of them tested negative for IgG antibodies to hepatitis B core antigen (anti-HBc). A booster dose at 10 years to anti-HBs negative subjects led to an anamestic response in 3/4 and 8/10 persons in Groups A and B, respectively. CONCLUSION: Immunological memory after vaccination against hepatitis B is maintained for at least 10 years.