Characteristics of Severe Bordetella pertussis Infection Among Infants ≤90 Days of Age Admitted to Pediatric Intensive Care Units - Southern California, September 2009-June 2011.

Bordetella pertussis infection can cause severe illness and death among young infants.We collected demographic and clinical information from the medical records of infants who were ≤90 days of age and hospitalized for pertussis in 5 Southern California pediatric intensive care units (PICUs) from September 1, 2009 to June 30, 2011. Infants who died or were diagnosed with pulmonary hypertension were considered to have more severe pertussis.Thirty-one infants were admitted to a participating PICU. Eight infants had more severe infections, 6 infants had pulmonary hypertension, and 4 infants died. The 8 infants with more severe infections had white blood cell counts that exceeded 30 000, heart rates that exceeded 170, and respiratory rates that exceeded 70 more rapidly after cough onset than the 23 infants with less severe illness.Identifying higher-risk infants earlier might allow for more rapid implementation of interventions.