A simplified schedule to integrate the hepatitis B vaccine into an expanded program of immunization in endemic countries

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 pertussis vaccine, Results: By age 9 months, none of group A and 4 (7%) group B infants were seropositive 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 mIU/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 incidences of adverse reactions were within an expected and acceptable range. Conclusions: The simplified vaccination schedule to integrate the hepatitis B vaccine 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.