CHANGES OF HBs-Ab LEVELS FOR 49 MONTHS AFTER THE HB VACCINATION

Abstract

Eighty nine healthy volunteers working at medical institution were given inactivated HB vaccine and followed up changes of HBs-Ab levels for 49 months.
Three doses of vaccine induced antibody in 70.5% out of 78 vaccine recipients at 28 weeks after the first dose. Active immunization occurred more frequently in female than in male.
At 49 months after the first dose, HBs-Ab positive rate decreased to 37.4% out of 32 subjects. All of those positive volunteers have had high HBs titer (Cut off index≥50) at 7 months after the first dose. But there was no sex or age difference in HBs-Ab titer.
These results suggest that inactivated HB vaccine is useful for active immunization of HBs-Ab. However, further investigation is needed to make clear whether re-vaccination is necessary or not.