Phase III Randomized, Double-Blind, Placebo-Controlled Study of Acellular and Whole-Cell Pertussis Vaccines

Overview

OBJECTIVES: I. Compare the efficacy of 2 acellular pertussis vaccines vs. whole-cell pertussis vaccine vs. placebo in infants living in Italy. II. Compare the relative protection of each of the acellular vaccines vs. the whole-cell vaccine vs. laboratory-confirmed pertussis. III. Assess the relative efficacy of the acellular vaccines with respect to one another. IV. Assess the immunogenicity of acellular vs. whole-cell vaccines in the study population. V. Compare the frequency of adverse events with each vaccine. VI. Compare the frequency of adverse events attributable to the pertussis component in each of the 3 vaccines. VII. Assess alternative laboratory diagnostic techniques for pertussis in estimating vaccine efficacy, i.e., mucosal immune response, DNA probes, or antibody response to other components of the organism. VIII. Assess the relative efficacy estimates of each vaccine, using clinical criteria to compare the relative incidence rates in each vaccine group.

PROTOCOL OUTLINE: This is a randomized, double-blind study. Patients are stratified by participating institution and randomly assigned to 1 of 3 vaccines and a placebo vaccine in a 3:3:3:1 ratio. One group receives diphtheria-tetanus-pertussis (DPT) vaccine containing filamentous hemagglutinin (FHA), Pt-9K/129G, and 69 kDA outer membrane protein (OMP). A second group receives DPT containing FHA and OMP. The third group receives DPT containing whole-cell pertussis. The control group receives diphtheria-tetanus (DT) vaccine. All vaccines are administered as an intramuscular or deep subcutaneous injection at 6-12, 13-20, and 21-28 weeks of age. The first vaccine is given at week 12 if hepatitis B or other immune globulin was given at birth. All patients receive a DT booster at 11 months, and are followed every 4 weeks for approximately 20 months.