Background

• Caused by the bacterium Bordetella pertussis (occasionally Bordetella parapertussis)
• Infants less than 6 months of age are at greatest risk of complications (apnoea, severe pneumonia, encephalopathy) and are most commonly infected by spread from family members 
• Can occur in immunised children but the illness is generally less severe
• Patients are infectious just prior to and for 21 days after the onset of cough, if untreated

Assessment

Diagnosis is largely clinical

History

• Classic whooping cough: Cough and coryza for one week (catarrhal phase), followed by a more pronounced cough in spells or paroxysms (paroxysmal phase)
• Pertussis can also present as a non-specific persistent cough
• Vomiting often follows a coughing spasm
• Infants may develop apnoea and/or cyanosis with coughing spasms
• Close contact with a case of Pertussis may raise suspicion 
• Other family members frequently have a cough (>70% of household contacts are also infected)

Examination

• Often, there are no clinical signs. Children are usually well between coughing spasms
• Observation of coughing spasms may be helpful
• Fever is uncommon

Investigations

• Laboratory confirmation is not necessary for diagnosis, but may be helpful for infection control
• A nasopharyngeal aspirate/swab for PCR is the investigation of choice. The test is usually negative after 21 days, or 5-7 days after effective antibiotic therapy has been commenced
• Pertussis serology (IgA) may be detectable 2 weeks after the onset of the illness but rarely affects clinical management

Management of patient

Antibiotics

Consider antibiotics if:

• Diagnosed in catarrhal or early paroxysmal phase (may reduce severity)
• Cough for less than 14 days (may reduce spread; reduces school exclusion period)
• Admitted to hospital
• Complications (pneumonia, cyanosis, apnoea)

Antibiotic options:

Neonates:

• Azithromycin 10 mg/kg oral daily for 5 days

Children who cannot swallow tablets:

• Clarithromycin liquid 7.5 mg/kg/dose (max 500 mg) oral BD for 7 days

Children who can swallow tablets:

• Azithromycin (for children = 6 months old): 10 mg/kg (max 500 mg) oral on day 1, then 5 mg/kg (max 250 mg) daily for 4 days
  

If macrolides are contraindicated:

• Trimethoprim-sulphamethoxazole (8-40 mg per mL)
  • 0.5 mL/kg (max 20 mL) BD for 7 days

Control of diagnosed case

• Exclude from school and presence of others outside the home (especially infants and young children) until received 5 days of therapy, or coughing for more than 21 days 

Vaccination

• Unimmunised or partially immunised children diagnosed with pertussis should still complete the pertussis immunisation schedule

Notification

Notify all cases (suspected or confirmed) of pertussis to the Communicable Diseases Section, DHS, Victoria. Tel: 1300 651 160 or Fax: 1300 651 170

• DHS information on pertussis
• Notification info, and notification form

Treatment of contacts

Antibiotic Prophylaxis:

Notes:

• Prophylaxis is aimed at preventing spread to infants <6 months
• There is little evidence that antibiotics prevent transmission outside of household settings, and side effects (especially gastrointestinal) are relatively common
• Transmission requires close contact (exposure within 1 metre for more than 1 hour) but can be less for young infants
• Most school-aged children who are fully vaccinated and do not have symptoms do not require prophylaxis
• Management of immunodeficient contacts should be made on a case by case basis
• Management of outbreaks may differ from below and will be conducted by DHS

Prophylaxis table: 

Antibiotic options:

• Prophylaxis regimen same as for treatment (refer above)

Vaccination:

• Close contacts that are not up to date with their pertussis immunisation should be given DTPa or dTpa as soon after exposure as possible
• Consider dTpa for adults who have not had pertussis-containing vaccine in the last 10 years

School exclusion:

• Unimmunised (<3 doses) household and close childcare contacts less than 7 years of age must be excluded from school or child care for 14 days from the last exposure to infection OR until they have taken 5 days of effective antibiotics

When to admit/consult local paediatric team

• Infants less than 6 months of age
• Any child with complications (apnoea, cyanosis, pneumonia, encephalopathy)

When to consider transfer to tertiary centre

• Any child with complications (apnoea, cyanosis, pneumonia, encephalopathy)
  
  For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.
  

Parent information sheet

• Parent information