Pertussis for health professionals

Pertussis (whooping cough) is a bacterial infection of the nose and throat caused by Bordetella pertussis.

Pertussis is highly infectious, spreading by respiratory droplets to 70 to 100% of susceptible household contacts and 50 to 80% of susceptible school contacts. In Australia, epidemics usually occur every three to four years. In recent years many cases of pertussis have been recognised in adults and adolescents due to waning immunity. These individuals are a significant source for the transmission of pertussis to infants.

Pertussis is a notifiable condition

Clinical presentation and outcome

Pertussis is a prolonged coughing illness with clinical manifestations that vary by age. Subclinical infections may occur. Illness usually occurs in three phases:

  • Catarrhal (non-specific): rhinorrhoea, mild cough with or without low grade fever.
  • Paroxysmal (after 1 to 2 weeks): paroxysmal cough which may end in vomiting, cyanosis and/or a high pitched inspiratory whoop. In adults, post-tussive vomiting is strongly suggestive of pertussis.
  • Convalescent: decreased intensity of cough and paroxysms, may last for months.

The most common complication is pneumonia caused either by B. pertussis infection itself, or co-infection with viral respiratory pathogens such as respiratory syncytial virus (RSV). Encephalopathy is a rare complication.

Infants

Infants may present with gagging, gasping, cyanosis, apnoea or non-specific signs such as poor feeding or seizures.

Adults

Adults and children partially protected by vaccination can present with illness ranging from a mild coughing illness to classical pertussis.

Incubation period

The incubation period ranges from four to 21 days, usually 7 to 10 days.

Infectious period

Cases are infectious from the onset of catarrhal symptoms. Communicability gradually decreases and is negligible three weeks after onset of cough. A case is considered non-infectious (even if the polymerase chain reaction (PCR) result is still positive) at whichever time is the earlier of:

  • 14 days after onset of paroxysmal cough (if the onset is known), or
  • 21 days after the onset of any cough, or
  • completion of five days of a course of an appropriate antibiotic (see latest version of Therapeutic Guidelines: Antibiotic).

Diagnosis

Diagnosis is most accurately made by Nucleic Acid Testing (NAT), also known as PCR, of nasopharyngeal aspirates or swabs or throat swabs, combined with clinical history.

Treatment

Appropriate antibiotic therapy, given in the early stages of infection, may prevent or lessen the severity of symptoms. Treatment within two weeks of onset of the cough reduces the spread of the disease, though it may not lessen symptoms.

Prevention

A person with pertussis should be excluded from child care, preschool, school or work while infectious: whichever time is the earlier of:

  • 14 days after onset of paroxysmal cough (if the onset is known), or
  • 21 days after the onset of any cough, or
  • completion of 5 days of a course of an appropriate antibiotic (see latest version of Therapeutic Guidelines: Antibiotic).

Antibiotic treatment of the person with pertussis, if started within two weeks of the onset of symptoms, will reduce the spread of infection. If there is a young child aged less than six months of age in the same household as the person with pertussis or a woman in the late stages of pregnancy, it is recommended that all household members receive preventive antibiotics.

Any household, child care, preschool, school or work contacts of a person with pertussis should seek medical advice if they develop any symptoms.

Seek advice from public health authorities regarding exclusion of contacts in a child care setting.

Immunisation

Immunisation is the best way to prevent pertussis. A three dose primary course of pertussis vaccination is recommended in infants (at 6 weeks, 4 months and 6 months). A pertussis booster dose is also recommended:

  • At 18 months to reduce pertussis notifications in the 1 to 3 year age group and to reduce transmission to younger siblings.
  • At 4 years of age.
  • For adolescents 10 to 17 years (ideally 11 to 13 years). This is usually given in Year 8 as part of the School Based Immunisation Program.
  • For women from 20 weeks gestation in every pregnancy (20-32 weeks optimal). If a mother was not vaccinated during pregnancy, maternal vaccination is recommended as soon as possible after birth and preferably before hospital discharge.

A pertussis booster dose is also recommended in the following groups (if more than 10 years since previous dose):

  • adult household contacts and carers of infants less than 6 months of age (at least 2 weeks before beginning close contact with the infant)
  • adults working with infants and young children aged less than 4 years
  • all health care workers
  • adults aged 50 years and older than 65 years
  • travellers (or for high risk travel, if more than 5 years have elapsed since the last dose of booster)
  • any adult who wishes to reduce the likelihood of becoming ill with pertussis.

Notification

Pertussis is a notifiable condition under the South Australian Public Health Act 2011. Notify any suspected or confirmed cases to the South Australian Communicable Disease Control Branch. Notify online or download and fax the purple notification form to (08) 7425 6696.

Resources for health professionals

National Guidelines for Public Health Units: Pertussis (2013) developed by the Communicable Diseases Network Australia (CDNA)

Pertussis: Management Guidelines for General Practice flowchart

A flowchart for General Practitioners (GP) (PDF 178KB) detailing the clinical and public health management of patients either suspected of having or who have a confirmed diagnosis of pertussis.

Pertussis (You’ve Got What?)

Pertussis (You’ve Got What?) is a fact sheet for patients about the cause, signs, symptoms, treatment and prevention of pertussis.