Efficacy of Acellular Pertussis Vaccine in Early Childhood After Household Exposure

Objective. —To evaluate the efficacy of a three-dose primary vaccination with a diphtheria-tetanus tricomponent acellular pertussis vaccine against "typical" pertussis, defined as a spasmodic cough of 21 days or longer with confirmation of Bordetella pertussis infection by culture or serology. Design. —Passive monitoring for suspected first household (index) cases of typical pertussis in six areas in Germany comprising 22 505 children vaccinated with study vaccine at 3, 4, and 5 months of age. Blinded, prospective follow-up of household contacts of index cases for incidence and progression of pertussis. Setting. —Six areas in Germany with a high incidence of pertussis. Subjects. —Four hundr…