Antibody response and reactions to completion of a four-dose series with a two- or three-component acellular pertussis vaccine compared to whole cell pertussis vaccine.

We compared the reactions and immunogenicity of DT acellular pertussis (DTaP) vaccines containing pertussis toxoid (PT) and filamentous haemagglutinin (FHA) (2-component DTaP) or PT, FHA and pertactin (PRN) (3-component DTaP vaccine) with a whole cell (DTwP) vaccine as a fourth-dose booster in 158 children (15-20 months old) who had received 3 primary vaccine doses with the same vaccines at 2, 4 and 6 months of age. Randomization was 3:1 for DTaP:DTwP and all children received concomitant oral polio vaccine (OPV). Fever (> 38 degrees C), irritability, local injection site erythema (> 10 mm), swelling (> 10 mm), and pain (moderate or more) were assessed for 72 h after booster vaccination. DTwP vaccinees had a higher incidence of fever (29.4%) and injection-site pain (45.7%) than 3-component DTaP vaccinees (fever, 9.6%, p < 0.02; injection-site pain, 3.8%, p < 0.01); 2-component DTaP vaccinees had less injection-site pain (8.3%, p < 0.01). Pre- and post-vaccination immunoglobulin G (IgG) antibody was measured by enzyme-linked immunosorbent assay (ELISA). Pre- and post anti-PT levels were similar for all 3 vaccine groups. Anti-FHA antibody was higher pre- and post-vaccination for both DTaP vaccine groups compared with the DTwP vaccinees (p < 0.01 for all comparisons). For 3-component DTaP vaccinees, anti-PRN antibody was higher pre- and post-vaccination compared to DTwP vaccinees (p < 0.01 for both comparisons). Tetanus antibody was higher pre- and post-vaccination for DTwP versus both DTaP vaccine groups, and diphtheria antibody was similar pre- and post-vaccination for all 3 groups. These 2- and 3-component DTaP vaccines produce less common reactions and comparable or higher antibody to the components they contain (except tetanus) than DTwP vaccine when given as a booster to 15- to 20-month-old children previously primed with the same vaccine.