Pertussis transmission in a neonatal intensive care unit — Arizona, 2011

Background: During September 13—15, 2011, hospital B reported 3 pertussis cases, including 2 confirmed by Bordetella pertussis isolation among infants discharged <30 days previously from a 71-bed neonatal intensive care unit (NICU A). We investigated NICU A to determine the extent of the outbreak, factors contributing to health care-associated transmission, and outbreak costs. Methods: Case definition was a cough >14 days during July 28—September 19 in a NICU-associated person. We observed NICU A practices and interviewed the parents of 35 hospitalized infants and 35 health care workers (HCW) furloughed for cough illness. Costs were calculated using HCW wages, time furloughed, the provision of vaccine, chemoprophylaxis and diagnostic testing, and NICU A labor costs. Results: We identified 15 case-patients; 5 infants (aged 1—15 weeks; 5 female), 10 HCWs (aged 32—50 years; 6 female). The index patient was an infant aged 7 weeks (gestational age 28 weeks) who experienced apnea on July 28 and cough on August 14 in NICU A; she had not been isolated. Pertussis was diagnosed after transfer to hospital B on September 9. Spacing of NICU A beds (16 inches apart), a 4:1 patient-to-nurse ratio, and absence of personal protective equipment (PPE) use were observed. Outbreak costs ($97,800) were primarily influenced by HCW furloughs ($55,349) and NICU A labor costs ($16,809). Of 365 HCWs, 330 required pertussis vaccine. Conclusions: This costly health care—associated pertussis outbreak might have been prevented with heightened awareness of apnea as a pertussis sign, compliance with HCW pertussis vaccination recommendations, and enforcement of PPE for HCWs with cough illness.