Clinical Drug Experience Knowledgebase

Adacel® (TdaP-Tetanus, Diphtheria, Acellular Pertussis) Booster Vaccination of Acellular Pertussis Vaccine-primed Individuals for Cell Mediated Immunity Assay Development

Pertussis, known as "whooping cough", is caused by the bacterium Bordetella pertussis which was discovered over a century ago. Human vaccines were developed in the subsequent two decades and routine childhood immunization has been practiced for over 60 years. Yet, B. pertussis remains a significant cause of morbidity in children and adults worldwide. Globally, about 20-40 million cases of pertussis are reported each year, with about 400,000 cases being fatal. The incidence of pertussis is highest and the severity the greatest in children under 6 months of age. Vaccination and natural infection are not protective for life, and the reason is unclear. The epidemiologic features of B. pertussis infections in older individuals who are only partially immune from prior infections and immunizations are not well understood. Clarification is important, in light of studies that suggest that pertussis is a cause of prolonged cough illness in adults who serve as the reservoir of B. pertussis and are the major source of infection for infants in whom the disease has substantial morbidity and mortality. With the considerable increase in cases and outbreaks, there is an imminent need for improved immunogenic and efficacious pertussis vaccines, paired with the best tools to evaluate vaccines and vaccine programs.

VaxDesign has proposed two studies for acellular vaccine primed (acP) versus whole cell vaccine primed (wcP) donors, to further develop and validate a number of practical assays for use as biomarkers and to define a baseline readout for pertussis vaccinations from these two cohorts. In addition, these assays will be optimized to use the small blood volumes that are routinely available from clinical studies. In contrast to measuring humoral immune responses, the cell mediated immune response (CMI) is a substantially more challenging parameter to assess and thus the sample volumes required for the study must be large enough to allow the multiple different assessments. In this study, samples will be taken to evaluate transcriptomics, and humoral and cellular immunity over a one month period following vaccination. The collaboration with the Canadian Center for Vaccinology (CCfV) offers a unique opportunity of easily accessing acellular vaccine primed individuals.