LONG-TERM ANTIBODY PERSISTENCE AFTER BOOSTER VACCINATION WITH COMBINED TETRAVALENT DIPHTHERIA, TETANUS, WHOLE-CELL BORDETELLA-PERTUSSIS ANDHEPATITIS-B VACCINE IN HEALTHY INFANTS

Combining HE vaccine with routine paediatric vaccines has been recogni zed as the best means of universal vaccination against hepatitis B. Ou r objective was to evaluate the long-term antibody persistence of such a combined vaccine in an area of high hepatitis B endemicity. We have shown that a DTPw-HB vaccine was safe and immunogenic when given as a booster dose at 18 months of age. One month after the booster dose of DTPw-HB vaccine, at least 97.8% of subjects had seroprotective anti-H BsAg levels, and 1 year later at least 93.9% of these subjects remaine d seroprotected against HBsAg. Immune responses to the DTPw components were similar or greater than those of the commercial DTPw vaccine giv en to the control group. This DTPw-HB vaccine, which showed good long- term anti-HBsAg antibody persistence, could advantageously replace sep arate DTPw and HE vaccines in areas of high hepatitis B endemicity in terms of clinical, economic and strategic benefits.