A simplified schedule to integrate the hepatitis B vaccine into an expanded program of immunization in endemic countries Chin-Yun Lee, MD, Ping-lng Lee, MD, Li-Min Huang, MD, PhD, Jong-Min Chen, MD, and Mei-Hwei Chang, MD From the Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan, Re- public of China Objective: To investigate the safety, immunogenicity, and efficacy of a simplified hepatitis B vaccination schedule. Methods: The second dose of hepatitis B vaccine and the first dose of diphtheria- tetanus-pertussis (DTP) vaccine were given simultaneously at age 6 weeks. The second dose of DTP vaccine was given at age 3.5 months. The third dose of DTP vaccine and the third dose of hepatitis B vaccine were given at age 5.5 months. One hundred three infants (group A) born to mothers without hepatitis B surface antigen (HBsAg) received DTP with whole-cell pertussis vaccine. Fifty-five infants (group B) born to mothers with HBsAg and hepatitis B e antigen received DTP with acellular pedussis vaccine. Results: By age 9 months, none of group A and 4 (7%) group B infants were sero- positive for HBsAg. The protective efficacy against the hepatitis B carrier state in these infants at high risk was 92%. Antibody to hepatitis B surface antigen was 10 mlU/ml or greater in 99 (96%) of group A infants and in 50 (91%) of group B infants. Both the acellular and whole-cell DTP vaccines were immunogenic, and the in- cidences of adverse reactions were within an expected and acceptable range. Conclusions: The simplified vaccination schedule to integrate the hepatitis B vac- cine into the Expanded Programme of Immunization was safe, immunogenic, and effective. This schedule may improve vaccine compliance and be applied to DTP and hepatitis B combination vaccines now under investigation. (J Pediatr 1997; 130:981-6) The carrier rate for hepatitis B in the Taiwanese general population has been 15% to 20%, and perinatal hepatitis B virus transmission has accounted for 40% to 50% of the car- tier pool. 1, 2 7?o prevent HBV-related chronic liver disease, a mass hepatitis B vaccination program was launched in Submitted for publication Feb. 12, 1996; accepted Oct. 18, 1996. Supported by Department of Health, Executive Yuan, Republic of China, grant Nos. DOH-H8007, DOH-H8107, and DOH-H8205. Reprint requests: Chin-Yun Lee, MD, Department of Pediatrics, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei, Taiwan, Republic of China. Copyright © 1997 by Mosby-Year Book, Inc. 0022-3476/97/$5.00 + 0 9/21/78808 Taiwan in 1984. 3 A recent serologic survey in Taipei showed that the overall prevalence rate of hepatitis B surface antigen in children younger than 12 years had decreased from 9.8% in 1984 to 1.3% in 1994. 4 Mass HB vaccination has been proved to be a powerful strategy to combat HBV-associated disease in Taiwan. According to the current vaccination schedule, HB vac- cines are given at birth and at ages 1 and 6 months. Diph- theria-tetanus-permssis and oral polio vaccines are given at ages 2, 4, and 6 months. Four clinic visits are required to complete the vaccination schedule before age 6 months. Current experiences suggest that high compliance is difficult to achieve with many injections on separate months. 5 In It- aly, the highest compliance rate was observed in the babies 981