Whooping cough overview
What is whooping cough?
Whooping cough is a highly infectious bacterial infection that affects people of all ages, but is most severe in children. It was first recognised after a whooping cough epidemic in Paris in 1578. It was then known as the ‘dog bark’, the ‘chin’ cough or ‘kin’ cough, meaning ‘convulsive’ cough.
The disease causes sudden attacks of an irritating cough that often end in a high-pitched whooping sound as the child takes a breath. Although immunisation has reduced its severity, it is still a common infection. Regular epidemics occur every 3 to 4 years. It is particularly severe in children less than one year of age.
Severity of whooping cough
If your child contracts whooping cough and they have not been vaccinated, they are more likely to develop pneumonia. A severe case of whooping cough or pneumonia in a young child could result in brain damage or death. If your child has never had the disease and has not been vaccinated against it, they are likely to get whooping cough if they come into contact with the bacteria. Whooping cough is also dangerous in elderly people, but tends to be less severe in adolescents and adults.
What causes whooping cough?
Whooping cough is caused by the bacterium Bordetella pertussis, although sometimes other bacteria can cause a pertussis-like syndrome. Bacteria enter the air passages and damage the lining of the windpipe and the main air passages in the lungs. The inflamed airways produce more mucus which then causes the irritating cough. The bacteria are passed from person to person by the infected mucus during coughing or sneezing.
What are the symptoms of whooping cough?
The symptoms of whooping cough commonly develop about 7 to 10 days after exposure to the bacteria, but can occur any time from a few days to a few weeks. Whooping cough symptoms can be divided into 3 stages. The cough commonly persists for up to 3 months.
The first (catarrh) stage
The first stage resembles the common cold, with a mild occasional cough, loss of appetite, runny nose, sneezing and possibly a slight fever. It is not common, however, for whooping cough to cause a fever. It is highly contagious at this stage, but difficult to diagnose, as whooping cough can be mistaken for bronchitis.
Nose and throat swabs that detect the pertussis bacteria will work only in the early stages of the disease. If your doctor suspects that your child has whooping cough because of the classic cough symptoms, they will take a swab and send it to the laboratory to make sure of the diagnosis. Throat swabs can detect pertussis germs up to 5 weeks after the onset of illness.
Blood tests can also be done for pertussis, but these are not always reliable or easy to interpret, so they are not thought to provide a definitive diagnosis. They only become positive 3-4 weeks after the onset of illness, and a single test may not be diagnostic.
The second (paroxysmal) stage
The second stage begins after 7 to 14 days. It is known as the paroxysmal stage due to the coughing spells. These coughing spells may produce plenty of mucus and the cough may finish with a loud whoop. Choking on the mucus can cause vomiting. Many young children diagnosed with whooping cough may not necessarily have the typical ‘whoop’. Often whooping cough may be in an older child who has been vaccinated and is partially immune, and they may not have the classic 'whoop' . Children may turn red or blue during the coughing fits. The persistent coughing spells can cause a child to stop breathing temporarily. Complications such as pneumonia or middle ear infections are more likely to develop at this time.
The third (convalescent) stage
The third stage (convalescent) is when the coughing and vomiting starts to subside. Sometimes, the coughing can start again months later if the child develops an upper respiratory tract infection.
In adolescents and adults, or children who have been vaccinated, the disease is often milder and people may even not show any symptoms, or they may have mild cough or a persistent cough.
Your doctor may suspect infection with whooping cough from the symptoms, or from witnessing the coughing. Swabs from the nose or throat or blood tests are usually used to confirm the diagnosis.
Whooping cough treatment
Most cases of whooping cough can be treated at home, but it depends on how severe the whooping cough symptoms are. Others will need to be treated in hospital. Young babies less than 6 months may need to be hospitalised. An antibiotic (such as azithromycin, clarithromycin or trimethoprim/sulfamethoxazole) will be prescribed if it is less than 3 weeks since the onset of illness. This is primarily to reduce the risk of transmission and may have little impact on the course of the disease. People are infectious for 3 weeks after the onset of cough, or until they have completed 5 days of appropriate antibiotics.
People who have been in close contact with someone with whooping cough, such as members of the same household, are at increased risk of developing the infection. Therefore, antibiotics are often given to close contacts who are at higher risk themselves (e.g. children under 6 months or immunosuppressed people) or who are at risk of transmitting the disease to those who are at high risk (e.g. childcare workers or healthcare staff) .
What you can do
Increased comfort for young children will aid recovery. Small healthy meals and fluids can be given to your child. Using steam in the bedroom or sitting the child on your knee in a steamy bathroom may give some temporary relief, however, the risk of burns is very real; never leave your child unsupervised. Cough medicine is of little value.
Caring for a child with whooping cough is hard work, especially as the cough is often worse at night. Ask family and friends to help so you can catch up with sleep. Keep your child away from others to prevent the infection spreading.
Exclusion from school, childcare or work
People with whooping cough need to stay away from work, school or childcare facilities until they have been on antibiotics for 5 days or they have had the cough for more than 3 weeks. If there is an outbreak of whooping cough and your child is not immunised they will have to stay away from their kindergarten or school until the outbreak is over. Children who are household contacts of the infected person and who have received fewer than 3 doses of pertussis vaccine need to stay off school or childcare for 21 days after the last exposure to infection, or until they have taken 5 days of a course of antibiotics.
Immunisation for whooping cough
The best way of preventing or reducing the severity of whooping cough is to be immunised. There are very few medical reasons why a child should not have pertussis immunisation. It is now accepted that contraindications (reasons why a child should not have the immunisation) have been overstated in the past. Newer vaccination formulations mean that previously troublesome post-vaccination symptoms, such as fever, are much less common than was the case with previous versions.
In Australia, immunisation against whooping cough is recommended at age 2, 4, and 6 months as part of the National Immunisation Program Schedule. The 2-month dose can be given as early as 6 weeks of age.
Two booster doses are recommended - one at 18 months and one at age 4 years. An additional booster dose is recommended for adolescents between 10 and 17 years.
In addition, To protect very young babies who are most at risk themselves, a single booster dose of adult formulation pertussis vaccine (dTpa) is recommended for:
- all women in the third trimester of pregnancy (preferably between 28 and 32 weeks. This is recommended with each pregnancy, even if close together. Vaccination at this time means that the baby will be born with some of the mother's antibodies to pertussis (passive immunity) and so have some protection during the most vulnerable newborn stage;
- fathers of young children;
- grandparents; and
- other carers of young children.
This is because the protective efficacy of the vaccine wears off over time and their immunity will have been reduced.
2.NHS Choices. Whooping cough. http://www.nhs.uk/conditions/Whooping-cough/Pages/Introduction.aspx (accessed July 2016).