Pertussis (Whooping cough)

- Notify Public Health.


Jump to Therapy


- For contact prophylaxis recommendations, see Prophylaxis for Contacts of Communicable Diseases.

- Persistent cough (≥ 6 days) in adolescents may indicate whooping cough in up to 32%, even in immunized individuals especially if last pertussis vaccination more than 5 years prior.

- Typical course of pertussis:

1) catarrhal phase - lasts 1-2 weeks; most contagious

2) paroxysmal phase - 3-6 weeks. Many children < 6 months of age do not develop paroxysmal cough or inspiratory whoop.

3) convalescent phase - > 6 weeks (mean duration of cough is 6 weeks).



- cough present for up to 3 weeks - order culture and PCR of posterior nasopharynx (aspirate/swab).

- cough present > 3 weeks - order PCR (beyond 4 weeks, PCR likely to be negative).


Antibiotic therapy

- Antibiotic therapy may reduce the duration or severity of symptoms (only if started in catarrhal phase) and limits transmission to susceptible contacts. Because viable organisms can be recovered from untreated patients for 3 weeks after onset of cough, a 5-7 day course of antibiotics is recommended during the first 4 weeks of illness.

- For individuals likely to be in contact with high risk contacts (infants, pregnant women in 3rd trimester, health care workers, child care workers who care for infants), a 5-7 day course of antibiotics is recommended during the 6-8 weeks after onset of illness.

Usual Pathogens

Bordetella pertussis


Empiric Therapy Dose Duration
  <6 months  
Azithromycin 10mg/kg (max 500mg) PO daily 5 days
  ≥6 months  
  10mg/kg PO first day (max 500mg) then

5 days

  5mg/kg PO daily (max 250mg) x 4 days  
Clarithromycin 15mg/kg/d PO div bid 7 days


Empiric Therapy


TMP/SMX (if > 1 month old) 8mg TMP/kg/d PO div bid 10 days