Table 3.

Algorithm for the diagnosis of pertussis and clinical case definition of pertussis for surveillance purposes

Age groups	Algorithm for the diagnosis of pertussis		Clinical case definition of pertussis for surveillance purposes
	Clinical capabilities only	Access to laboratory facilities	Cough illness in a person with no or minimal fever
0–3 months	Cough of any duration which is not improving (seen as paroxysmal or not) Coryza (not becoming purulent) Afebrile/low-grade fever Cough and apnea Cough and seizures Cough and cyanosis Cough and emesis Pneumonia Co-infection with RSV or adenovirus potentially leading to expiratory distress and fever	Early stage (cough is < 3 weeks in duration)  Increased WBC ( ≥ 20,000 with ≥ 10,000 lymphocytes)  PCR and culturea	Cough and coryza with no or minimal fever PLUS: Whoop OR Apnea OR Posttussive emesis OR Cyanosis OR Seizure Pneumonia Close exposure to an adolescent or adult (usually a family member) with a prolonged afebrile cough illness
		Late stage (cough is > 3 weeks in duration)  PCR and cultureb,c
4 months–9 years	Paroxysmal non-productive cough of 7 days duration or more Coryza (not becoming purulent) Afebrile/low-grade fever Whoop Apnea Posttussive emesis Subconjunctival hemorrhage Cyanosis Sleep disturbance	Early stage (cough is < 3 weeks in duration)  PCR  Serology (IgG-PT), if ≥ 1 year after pertussis vaccination	Paroxysmal cough with no or minimal fever PLUS: Whoop OR Apnea OR Posttussive emesis Seizure Worsening of symptoms at night Pneumonia Close exposure to an adolescent or adult (usually a family member) with a prolonged afebrile cough illness
		Late stage (cough is > 3 weeks in duration)  Serology (IgG-PT), if ≥ 1 year after pertussis vaccination
≥ 10 years	Paroxysmal non-productive cough of 7 days duration or more Coryza (not becoming purulent) Afebrile/low-grade fever Whoop Apnea Posttussive emesis Subconjunctival hemorrhage Cyanosis Sleep disturbance Sweating episodes between paroxysms	Early stage (cough is < 3 weeks in duration)  PCR  Serology (IgG-PT), if ≥ 1 year after pertussis vaccination	Non-productive paroxysmal cough ≥ 2 weeks duration without fever PLUS: Whoop OR Apnea OR Sweating episodes between paroxysms Posttussive emesis Worsening of symptoms at night
		Late stage (cough is > 3 weeks in duration)  Serology (IgG-PT), if ≥ 1 year after pertussis vaccination

IgG immunoglobulin G, PCR polymerase chain reaction, PT pertussis toxin, RSV respiratory syncytial virus, WBC white blood cell

^aIn areas where PCR is not available, samples may be sent for culture confirmation to reference laboratories

^bFalse negatives are possible

^cSerology not informative in this age cohort

Source: Adapted from Cherry et al. [63]