Outbreak of pertussis among healthcare workers in a hospital surgical unit

background. In September 1999, a pertussis outbreak was detected among surgical staff of a 138-bed community hospital. Patients were exposed to Bordetella pertussis during the 3-month outbreak period. Objective. To describe the outbreak among surgical staff, to evaluate implemented control measures, and to determine whether nosocomial transmission occurred. Methods. Clinical pertussis was defined as acute cough illness with a duration of 14 days or more without another apparent cause; persons with positive culture, PCR, or serologic test results were defined as having laboratory-confirmed pertussis. Surgical healthcare workers ( HCWs) were interviewed regarding pertussis symptoms, and specimens were obtained for laboratory analysis. Patients exposed to B. pertussis during an ill staff member's 3-week infectious period were interviewed by phone to determine the extent of nosocomial spread. Participants. A total of 53 HCWs assigned to the surgical unit and 146 exposed patients. HCWs with pertussis were defined as case subjects; HCWs without pertussis were defined as non-case subjects. Results. Twelve (23%) of 53 HCWs had clinical pertussis; 6 cases were laboratory confirmed. The median cough duration in the 12 case subjects was 27 days ( range, 20-120 days); 10 (83%) had paroxysms. Eleven (92%) of 12 case subjects and 28 (86%) of 41 non-case subjects received antibiotic treatment or prophylaxis. Seven case subjects (58%) reported they always wore a mask when near patients. Of 146 patients potentially exposed to pertussis from the 12 case subjects, 120 (82%) were interviewed; none reported a pertussis-like illness. Conclusions. Surgical staff transmitted B. pertussis among themselves; self-reported data suggests that these HCWs did not transmit B. pertussis to their patients, likely because of mask use, cough etiquette, and limited face-to-face contact. Control measures might have helped limit the outbreak once pertussis was recognized.