Pertussis in Massachusetts, 1981-1991: incidence, serologic diagnosis, and vaccine effectiveness.

Massachusetts provides diphtheria-tetanus toxoid-pertussis (DTP) vaccine, and since 1980 has monitored pertussis with a statewide diagnostic service. The incidence of bacteriologically confirmed pertussis was 104.5 per 100,000 person-years in 1-month-old infants and declined progressively thereafter. Infants < 6 months old experienced disproportionate morbidity: 44% of bacteriologically confirmed pertussis, 64% of hospitalizations, and 71% of hospital days. Most children with pertussis had received < 3 DTP doses during childhood, whereas 87% of adolescents with pertussis had received > or = 4 doses. Serodiagnosis by single serum anti-pertussis toxin antibody ELISA increased the incidence of confirmed pertussis in persons 11-19 years old from 3.0 to 12.9 per 100,000 and in persons > or = 20 years old from 0.16 to 0.56 per 100,000. Bacteriologic methods underestimate pertussis incidence, but a single serum anti-pertussis toxin antibody ELISA is a practical method for population-based diagnosis in adolescents and adults.

Use of implantable intraperitoneal diffusion chambers to study Bordetella pertussis pathogenesis: growth and toxin production in vivo.

A new animal model for Bordetella pertussis infection is described. The system utilizes small chambers bounded by 0.22-micron filter membranes. The chambers are inoculated with B. pertussis, sealed, and surgically implanted into the peritoneal cavity of mice. The chamber system allows dynamic interchange of soluble host and bacterial factors, but not cells. We have used this system to study the growth of various clinical isolates and vaccine strains of B. pertussis, including an isogenic virulent/avirulent pair. All virulent strains tested grew well and had remarkably similar growth kinetics. We monitored cellular and humoral host responses, including the response to pertussis toxin. Antitoxin appeared 21-37 days after implantation of the chambers. The model allows us to dissociate the ability of an organism to grow in vivo from other properties (e.g., attachment and toxin production) that may be involved in pathogenesis.

Immunization of humans with polyribophosphate, the capsular antigen of Hemophilus influenzae, type b.

In human volunteers, single injections of purified polyribophosphate elicited antibodies detectable by passive hemagglutination and by serum bactericidal and opsonizing activities against viable Hemophilus influenzae, type b. All three activities rose by 2 wk to maximal levels, at which they remained for at least 6 months. Doses of 1 mug elicited antibody responses in nearly all recipients; higher doses of the antigen, however, produced larger increases in titer. Booster doses of 1 mug given at 6 months did not further increase the antibody titers. A tuberculin-like response was often observed at the site of injections given intradermally.