Objective:
To evaluate the spread of pertussis in a fully immunized eighth-grade class and the household contacts of two coindex cases of pertussis.
Design:
Survey of infected subjects and their contacts was performed using culture, direct fluorescent antibody assay, and serological assays to establish the diagnosis of Bordetella pertussis.
Setting:
Middle-class parochial school.
Participants:
A volunteer sample of 15 eighth-grade students and 13 household contacts of two identified cases of B pertussis infection.
Interventions:
All participants had medical histories (including immunization status) and laboratory evaluation for B pertussis infection (including nasopharyngeal specimens and serum samples) obtained initially and 30 days later. After initial evaluation, all subjects received erythromycin ethyl succinate therapy.
Main Outcome Measures:
Assessment of B pertussis infection as defined by positive nasopharyngeal culture, direct fluorescent antibody, or serological tests.
Results:
Laboratory evidence of B pertussis infection was found in eight (47%) of 17 immunized eighth-grade classmates and in three (23%) of 13 household contacts, all of whom were 12 years of age or older.
Conclusions:
Vaccine-induced immunity wanes by early adolescence. These older age groups may be infected with B pertussis and may serve as reservoirs of infection for other susceptible individuals.(Arch Pediatr Adolesc Med. 1994;148:153-157)