Clinical findings in Bordetella pertussis infections : results of a prospective multicenter surveillance study

OBJECTIVE: To study the clinical presentation of culture-confirmed pertussis in children and their contacts with cough illnesses in an outpatient setting. METHODOLOGY: In conjunction with a large pertussis vaccine efficacy trial in Germany, a central laboratory to isolate Bordetella species from nasopharyngeal specimens was established in Erlangen in October 1990. Pediatricians in private practices in southern Germany, the Saar region, and Berlin were encouraged to obtain nasopharyngeal specimens and clinical characteristics from patients with cough illnesses </=7 days' duration. Bordetella species were isolated by use of calcium alginate swabs, Regan-Lowe agar, and modified Stainer-Scholte broth. Clinical characteristics were determined by initial and follow-up questionnaires. RESULTS: From October 1990 to September 1996, 20 972 specimens were submitted, and B pertussis was isolated in 2592 instances (12.4%). Of the culture-proven cases, 50.7% were female, and the age range was 6 days to 41 years, with a mean and median of 4.3 years and 4.1 years, respectively. The following characteristics were noted. Only 4% of the patients had received pertussis vaccine. Of unvaccinated patients, 90.2% had paroxysmal cough, 78.9% demonstrated whooping, and 53.3% presented with posttussive vomiting; 5.7% had fever </=38 degrees C. The duration of cough was /=21 days of spasmodic cough.