Although there are a lot of the reports about the persistence of anti HBs titer of plasma derives HBV vaccine, it is difficult to find the follow up studies of the recombinant HBV vaccine. We performed this study to compare the persistence of anti HBs titer by vaccination schedule and the seronegative rate of 5 years later according to Anti HBs titer after basic immunization in neonatal period by recombinant HBV vaccination.

This study was performed on 420 neonates at Pusan Moon Hwa Hospital from April to December 1993, followed up for 5 years after basic immunization by recombinant HBV vaccine. The anti HBs titer test was done by radioimmunoassay(RIAAUSAB, Abbott laboratories). The positive anti HBs level that would protect against HBV infection was defined as a level equal to or greater than 10mIU/mL.

In this study the seronegative rate after 5 years was 5% in 2 month schedule group, 25.5% in 6 month schedule group(P>0.05). In 2 month schedule group the seronegative rate was 20% when anti HBs titer is lower than 200mIU/mL, 0% when more than 200mIU/mL(P>0.05). In 6 month schedule group the seronegative rate was 66.7% when anti HBs titer was lower than 200mIU/mL, 40% when 200~499.9mIU/mL, 23.9% when 500~999.9mIU/mL, 22.5% when more than 1000mIU/mL.

In this study the seronegative rate after 5 years of recombinant HBV vaccination was 5~25.5%. The persistence of anti HBs titer was statistically irrelevant to schedule. The seronegative rate after 5 years was statistically irrelevant to anti HBs titer after basic immunization.