Young children in a day care setting had a high rate of shedding and a low rate of transmission. No clinically significant illness occurred among children who received vaccine or placebo or in the child to whom the vaccine virus was transmitted.

No abstract

We evaluated pertussis-specific cell-mediated immunity (CMI) and humoral immunity in adolescents 3 years after they received an acellular pertussis booster immunization. Two hundred sixty-four adolescents were examined for immunoglobulin G antibodies, and 49 were examined for CMI against Bordetella pertussis antigens 40 months after receiving the booster. A control group of similarly aged adolescents who had received diphtheria and tetanus vaccination 3 years earlier was included for comparison. Pertussis-specific CMI persisted at greater than prebooster immunization levels. Although they had decreased by the 3-year follow-up, antibody levels remained significantly higher than prebooster immunization levels. Antibodies against pertussis antigens and CMI against filamentous hemagglutinin and pertactin were significantly higher in vaccinated adolescents than in control subjects. The acellular pertussis booster immunization provides long-term CMI and humoral immunity lasting for >or=3 years. The significantly higher immunity observed in the diphtheria, tetanus, and acellular pertussis vaccine recipients, compared with that in control subjects, indicates that these responses are more likely to have resulted from the booster immunization than from the boosting effects of natural B. pertussis infection.

Local reactions and pertussis toxin specific immunoglobulin E antibodies (PT-IgE) were investigated in healthy children following primary and booster immunization with a combined diphtheria tetanus acellular pertussis vaccine (DTPa) including pertussis toxin, filamentous haemagglutinin and pertactin. A primary series of DTPa was administered to 150 infants, and 104 of them received a booster dose of DTPa combined with inactivated polio vaccine at 2 years of age. PT-IgE was measured in serum samples from 72 children using a modified nitrocellulose RAST. Primary immunization was associated with low incidence of local reactions (1%-5%). After the booster dose 21% of children had a local reaction >/=20 mm. Local reactions after the booster dose tended to be more common in children who had experienced reaction at primary immunization. PT-IgE was detected in 18% and 86% of children following primary and booster vaccinations, respectively. Allergic and non-allergic children did not differ in PT-IgE responses. After primary immunization, elevated PT-IgE levels were found more often in children with a family history of allergy than in those without known allergy in the family. Children with local reactions had significantly higher pre- and post-booster PT-IgE levels and median post-booster pertactin IgG and diphtheria-IgG levels than children without local reactions. Conclusion Acellular pertussis immunization induces IgE antibodies to pertussis toxin, especially after booster vaccination. The higher median pre- and post-booster levels of pertussis toxin specific immunoglobulin E and post-booster levels of IgG to pertactin and diphtheria in children with local side-effects reflect a multifactorial immunological mechanism of such reactions.

The results of this study show that PCR assay can achieve the specific diagnosis of pertussis infection in a large proportion of infants even when antimicrobial treatment has killed the organisms and culture is no longer positive.