CDC Definitions of Clinical, Confirmed, and Probable Cases of Pertussis
| A clinical case is defined as an acute cough illness lasting ≥14 days in a person with at least one pertussis-associated symptom (ie, paroxysmal cough, post-tussive vomiting without other apparent cause, or inspiratory whoop) or, in an outbreak setting, ≥14 days of cough with no other symptoms. |
| A confirmed case is defined as a cough illness of any duration in a person from whom B. pertussis is isolated, or a case that meets the clinical case definition and is confirmed by polymerase chain reaction (PCR) or by epidemiologic linkage to a culture- or PCR-confirmed case. |
| A probable case meets the clinical case definition but is neither laboratory confirmed nor epidemiologically linked to a laboratory-confirmed case. |
| Confirmed and probable cases of pertussis should be reported to the National Notifiable Disease Surveillance System (NNDSS) of the US Centers for Disease Control and Prevention. |