PEDIATRICS Vol. 100 No. 6 December 1997, p. e10
Received Jun 13, 1997; accepted Jul 25, 1997.

From * Universitätsklinik mit Poliklinik für Kinder
und Jugendliche, Erlangen, Germany; and
Department of
Pediatrics, University of California Los Angeles School of Medicine,
Los Angeles, California.
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°C. The duration of cough
was
4 weeks in 37.9% and
3 weeks in 17.4%. Leukocytosis and
lymphocytosis (values above the age-specific mean) were observed in
71.9% and 75.9% of unvaccinated patients, respectively. The overall
complication rate was 5.8%, and pneumonia (29%) was the most frequent
complication. In infants <6 months of age, the rate of complications
was 23.8%. One death in a 7-month-old infant occurred.
Conclusions. Typical symptoms of pertussis were observed
in the great majority of patients regardless of age group. However, the
duration of cough was surprisingly short in one sixth of the patients.
These short illness cases would not be classified as pertussis
according to the World Health Organization clinical case definition,
which requires
21 days of spasmodic cough.