Immune responses to pertussis antigens eight years after booster immunization with acellular vaccines in adults

Pertussis-specific antibody and cell-mediated immune (CMI) responses were s tudied in adults 8 years after booster immunization with either a bicompone nt (pertussis toxin and filamentous hemagglutinin) or a monocomponent (pert actin) acellular vaccine and in age-matched healthy controls. The levels of vaccine-induced antibodies were also compared between the serum samples co llected before, 1 month, 4 years, and 8 years after immunization. Over the follow-up period, geometric mean values (GMV) of antibodies to the vaccine antigens decreased in both groups of vaccinees. However, the 8-year postimm unization GMV were 3-20 times higher than preimmunization GMV (all P values < 0.01). Moreover, both antibody and CMI responses to the vaccine antigens were significantly higher in the vaccinees than in the controls (all P < 0 .01 for antibody; all P < 0.001 for CMI responses). The results show that a ntibody and CMI responses induced by acellular pertussis vaccines can persi st for up to 8 years after booster immunization of adults primed with whole -cell vaccine. (C) 2000 Elsevier Science Ltd. All rights reserved.