Whooping cough is a highly infectious respiratory disease caused by the bacterium Bordetella pertussis. It can affect all age groups but most commonly occurs in children. Symptoms are usually mild in adolescents and adults but in children less than one year of age symptoms can be particularly severe. Whooping cough affects females more commonly than males, though the reason for this is not fully understood.
Whooping cough, also known as pertussis or 100 Day Cough, is typically spread by coughing and sneezing. If the condition is severe, hospital treatment may be necessary. In rare cases, the condition can be fatal. Whooping cough outbreaks tend to occur every three to five years in New Zealand: during a recent outbreak from August 2011 to December 2013 there were 379 new cases per month, subsequently reducing to an average of 70 cases per month.
The highest rates of disease occur in infants less than one year of age. Vaccination against whooping cough is part of the national immunisation schedule and plays an important role in reducing the spread of the disease.
Signs and symptoms
Whooping cough is normally characterised by severe coughing spasms followed by a gasp for breath that sounds like a “whoop”. However, in some cases this distinctive noise is not evident and symptoms may be similar to other coughs and colds.
The symptoms of whooping cough usually follow a cycle that lasts for a number of weeks. There are three distinct stages:
First stage (Catarrhal stage): lasting 1-2 weeks:
- Loss of appetite
- Slight fever
- Watery, running nose and eyes
- Fatigue
- Sneezing
- Irritating cough (particularly at night).
Symptoms experienced during this stage often resemble those of a common cold or mild bronchitis.
Second stage (Paroxysmal stage): usually lasting 1-6 weeks, but can continue for up to 10 weeks:
- Severe coughing spasms
- A high-pitched "whooping" sound when inhaling after a coughing spasm (the “whoop” sound may not occur with young infants)
- Vomiting or turning blue due to severe coughing or choking on mucous.
The coughing spasms characteristic of this stage may be triggered by such things as crying, feeding, overactivity or tobacco smoke. Where possible it is important to avoid exposure to potential triggers in order to reduce the frequency of coughing spasms.
Third stage (Convalescent stage): may last for months:
- During this stage symptoms subside, though subsequent respiratory infections, even months after the initial whooping cough infection, can cause a recurrence of the coughing spasms.
Transmission and incubation period
The whooping cough bacteria are spread from person to person in airborne droplets or by direct contact with infected throat or nasal discharges. Coughing and sneezing are the most common modes of transmission. Once infection with the whooping cough bacteria has occurred, the time until symptoms appear (incubation period) is usually between five to 10 days, though it can be as long as 21 days.
The contagious period is from seven days following infection with the whooping cough bacteria, to up to one month after the appearance of the coughing spasms, with the most contagious period being during the catarrhal stage.
If there is an outbreak of whooping cough it is advisable to keep uninfected children (especially those who are unimmunised) away from the source of the infection until after the contagious period has passed. Likewise, children with whooping cough should be removed from school or daycare until they are no longer infectious.
Diagnosis
Diagnosis of whooping cough will involve an assessment of the nature and history of the symptoms. The disease can be difficult to diagnose in its early stages because of its resemblance to a common cold or bronchitis. As the whooping cough bacteria can be detected in respiratory secretions, nose and throat swabs may be taken to confirm the diagnosis. A chest x-ray and blood tests may also be performed.
As whooping cough is a notifiable disease, the doctor who diagnoses it is required to notify a Medical Officer of Health.
Treatment
Antibiotics are used in the treatment of whooping cough. They are most effective in reducing the severity of whooping cough when given in the very early stages of the disease. Antibiotic treatment commenced once the disease is well established may be recommended to reduce the likelihood of the bacteria spreading but it may not reduce the severity of symptoms.
Antibiotics may also be prescribed to treat any secondary infections that may have developed. Prophylactic (preventative) antibiotic treatment may be recommended for other members of the household to prevent the spread of the disease in the community.
Further treatment of whooping cough is supportive and involves making the child comfortable. This should include:
- Bed rest
- Small frequent meals
- Maintaining fluid intake.
Use of a humidifier to warm and moisten the air may be helpful in soothing the airways and reducing coughing spasms. Sitting with the child in a steamy bathroom can also be beneficial.
Cough suppressant medicines are not effective in treating whooping cough.
In particularly severe cases of whooping cough, treatment in hospital may be necessary. This is most commonly required in infants under six months of age, with approximately 75% of those affected in this age group requiring hospitalisation.
Treatment in hospital may include:
- Administering oxygen
- Suctioning secretions and mucous
- Administering fluids through a drip in the hand or arm in order to prevent dehydration
- Monitoring for signs of complications
- Isolation from other children to prevent the spread of the disease.
Complications
Complications of whooping cough can include:
- Dehydration
- Pneumonia
- Brochiectasis
- Middle ear infection
- Temporary cessation of breathing (apnoea)
- Hernia (commonly in the groin) caused by excessive coughing
- Encephalopathy (disruption in brain function) eg: swelling, damage, seizures.
It is important to watch for any signs of complications. A doctor should be consulted immediately if complications are suspected.
Prevention, vaccination
To prevent the spread of the disease, immunisation is essential. Immunisation against whooping cough is given free to children as part of the national immunisation schedule. The whooping cough vaccine is given (in combination with vaccines against other diseases) at six weeks, three months and five months. The vaccines used are INFANRIX-hexa, INFANRIX-IPV and Boostrix. Children are not fully protected against whooping cough until they have had all three doses. As protection from the vaccine reduces over time, booster doses are given to children when they're four and 11 years old.
Vaccination in adults is designed to prevent the inadvertent transmission of the virus to infants who are at greatest risk. The Ministry of Health recommends that adults have a booster dose of the vaccine if:
- Their work involves regular contact with infants
- They are pregnant (between 28 and 38 weeks of pregnancy)
- They live with or care for infants under 12 months of age, even if the baby has been fully immunised.
Boosters should also be considered for other people who are vulnerable to whooping cough and at high risk of severe illness or complications (e.g. those with chronic respiratory conditions, congenital heart disease or immunodeficiency).
Further information and support
For further information about immunisations consult your GP or practice nurse, or contact:
Immunisation Advisory Centre
Freephone: 0800 IMMUNE (0800 46 68 63)
Website: www.immune.org.nz
Website: www.immune.org.nz
For further information and support about whooping cough consult your GP or practice nurse, or contact:
Plunketline
Freephone: 0800 933 922 (operates 24 hours a day, 7 days a week)
Freephone: 0800 933 922 (operates 24 hours a day, 7 days a week)
Healthline
Freephone: 0800 611 116 (operates 24 hours a day, 7 days a week)
Freephone: 0800 611 116 (operates 24 hours a day, 7 days a week)
References
Auckland Regional Public Health Service (2015). Pertussis (Whooping Cough) [Web Page]. Auckland: Auckland Regional Public Health Service. www.arphs.govt.nz/health-information/communicable-disease/pertussis-whooping-cough [Accessed: 03/05/17]
Immunisation Advisory Centre (2016) Pertussis (Web Page). Auckland: Immunisation Advisory Centre (IMAC) University of Auckland. www.immune.org.nz/diseases/pertussis [Accessed: 03/05/17]
Ministry of Health (2016) Whooping Cough (Web Page). http://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/whooping-cough [Accessed: 03/05/17]
Immunisation Advisory Centre (2016) Pertussis (Web Page). Auckland: Immunisation Advisory Centre (IMAC) University of Auckland. www.immune.org.nz/diseases/pertussis [Accessed: 03/05/17]
Ministry of Health (2016) Whooping Cough (Web Page). http://www.health.govt.nz/your-health/conditions-and-treatments/diseases-and-illnesses/whooping-cough [Accessed: 03/05/17]
Last Reviewed - May 2017