Five-year follow-up of immune response to hepatitis B vaccine in juveniles

The persistence of anti-HBs was investigated in 95 juveniles who received plasma-derived HBV vaccine (vaccine group) and 63 counterparts who got anti-HBs from natural HBV infection (infection group) for a period of five years. The positive rates of anti-HBs from the first to fifth year in the vaccine group are 97.89%, 98.95%, 81.05%, 78.95% and 72.63% respectively with one recipient remaining anti-HBs negative after being immunized with three dosages of 10 micrograms plasma-derived HBV vaccine in 0, 1st, 2nd month and the mean S/N values (GMV) are 30.94, 22.18, 13.61, 12.02 and 9.18 respectively. There are 26 recipients whose anti-HBs turned from positive to negative at the end of the study with a negative rate of 27.37%. The S/N GMVs in the infection group are 36.37, 27.33, 24.08 at the first, third and fifth year of the study, respectively. Both the S/N GMV and negative rate are lower than that of the vaccine group (P < 0.01). No one was found to have positive HBsAg or elevated ALT in both groups. Questions such as immune dosage, immune program and booster immunization in juvenile population are discussed.