0264-410X(95)00108-5 Vaccine, Vol. 13, No. 17, pp. 1685-1689, 1995 Copyright 6 1995 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0264-41 Ox/95 $1 O+O.OO zyxwvu A follow-up study of combined vaccination with plasma-derived and recombinant hepatitis B vaccines in infants Ping-Ing Lee, Chin-Yun Lee *, Li-Min Huang, Jong-Min Chen and Mei-Hwei Chang* zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA This study was aimed to evaluate the ejicacy and immunogenicity of combined hepatitis B vaccination with plasma-derived vaccine zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (PDV) and recombinant vaccine (RV). A total of 329 infants was recruited, including 224 high-risk infants born to hepatitis B e antigen-positive mothers and 105 low-risk infants born to hepatitis B e antigen-negative mothers. The high-risk infants rece~vedfour doses of hepatitis B vaccine at 0, 1, 2 and 12 months of age withJive diflerent schedules. Group Al and A2 infants were vaccinated with PD V as the$rst dose and R V (SB vaccine for group Al, MSD vuccine for group A2) as the remaining three doses. Group BI and group B2 infants were vaccinated with PDV as the$rst two doses and RV (SB vaccine for group 31, MSD vaccine for group B2) as the remaining two doses. Group C infants received four doses of PD V. Low-risk infants were ~~~ccin~ted Judith PDV at birth, and RV at I and 6 months of age (group DI, using SB vaccine; group 02, using MSD vaccine). At completion of vaccination schedules, 20 of 224 high-risk infants (9%) were positive for hepatitis B surface antigen. The overall protective ejicacy was 90%. Hepatitis B surface antibody (anti-HBs)-positive rate ranged between 94 and 100% among the remaining infants. The protective eficacy and immuno- genic&y were similar among groups except that the mean level of anti-HBs in group C, Df and D2 infants tended to be lower than that of the other four groups. To ensure an optimal immune response, four doses of vaccine are recommended in high-risk infants when two types of vaccine are to be used in combination. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Keywords: Hepatitis B; vaccination; immunogenicity The carrier rate for hepatitis B (HB) in the Taiwanese general population has been 15-20%, and perinatal hepatitis B virus (HBV) transmission has accounted for 40-50% of the carrier pool”. Although a chronic carriage of HBV in children is usually asymptomatic~,‘, chronic hepatitis, liver cirrhosis and hepatocellular carcinoma may develop in later life6. To combat HBV infection, an effective vaccine was first developed during the 1970s by purifying hepatitis B surface antigen (HBsAg) from the plasma of healthy carriers’. With the development of recombinant DNA technology, a new HB vaccine was produced in the mid-1980s by incorporating HBsAg-expressing vectors into the yeast’. Although both types of vaccine were highly efficacious and safe7-13, the plasma-derived Depa~ment of Pediatrics, National Taiwan Universi~ Hospital, 7 Chung-Shan South Road, Taipei, Taiwan, Republic of China. *To whom correspondence should be addressed. (Received 6 December 1994; revised 5 May 1995; accepted 30 May 1995) vaccine (PDV) is costly to produce and the supply of required HBsAg-positive serum cannot be assured. It is therefore inevitable that recombinant vaccines (RV) will replace PDV. Both types of HB vaccine comprise mainly of HBsAg. However, there are subtle differences between them: (1) the types of lipids present in the HBsAg differ; and (2) approximately 25% of the plasma-derived HBsAg is glycosylated, whereas the recombinant HBsAg is non- glycosylated’. When the supply of PDV becomes lim- ited, an important issue to be addressed is that whether these two types of vaccine can be used in combination. A combination of these two types of vaccine has been tried before by Pearl et a1.14 They concluded that the booster effect of RV was inferior to PDV in healthcare workers who had received two doses of PDV. They also suggested that there might be an accelerated drop in hepatitis B surface antibody (anti-HBs) when different vaccines were used in combination. Questions remained whether this is also true for high-risk infants born to hepatitis B e antigen (HBeAg)-positive carrier mothers, Vaccine 1995 Volume 13 Number 17 1685