The condition gets its name from a distinctive hacking cough, which is followed by a high-pitched gasp for air that sounds like a "whoop."
Before vaccines, approximately 157 people per 100,000 developed whooping cough in the United States.
There were peaks every 2-5 years. In 93 percent of cases, they were children under the age of 10. Experts say the real incidence at that time was much higher because not all cases were reported.
After the introduction of mass vaccinations in the 1940s, whooping cough rates dropped to less than 1 per 100,000 by 1970. Today, it mainly affects children who are too young to have completed the full course of vaccinations, as well as adolescents whose immunity has waned. However, since 1980, numbers have started to creep back up.
Contents of this article:
Here are some key points about whooping cough. More detail and supporting information is in the main article.
- Whooping cough is caused by the Bordetella pertussis bacterium.
- Children who are not vaccinated are 23 times more likely to develop whooping cough.
- The bacterium is spread in tiny droplets of water when the patient coughs and sneezes.
- Infants with whooping cough are usually admitted to hospital for treatment.
Symptoms of whooping cough
Whooping cough symptoms start off mild and progress.
Whooping cough symptoms usually appear 6-20 days after the Bordetella pertussis bacterium has infected the patient, in other words, pertussis has a 6-to-20 day incubation period.
The illness starts off with mild symptoms, which then get much worse before improving. Initial signs and symptoms of pertussis are similar to those of the common cold:
- blocked nose
- dry and irritating cough
- malaise (general feeling of being unwell)
- mild fever
- runny nose
- sore throat
- watery eyes
- diarrhea (sometimes)
The above signs and symptoms are typical during the first week, after which, they become more severe.
Later (paroxysmal) symptoms
During the second "paroxysmal" stage, symptoms include:
Severe bouts of coughing - a bout can last a couple of minutes. Sometimes, each bout comes so soon after the last that the patient has cluster bouts that last for tens of minutes. There are typically 10-15 bouts each day.
During a bout of coughing, the patient eventually gasps for air between coughs and also immediately after the bout is over, producing a "whoop" sound. This is less common in very young children and babies - they may gag or gasp, or even stop breathing temporarily.
Young children may become blue in the face (cyanosis) during a coughing bout. Although frightening for parents, it is virtually never as bad as it looks and breathing soon resumes.
Coughing bouts may be followed by vomiting; this is more frequent among young children and babies.
In adults and teenagers, whooping cough paroxysmal symptoms are less severe than in babies and young children - they are usually similar to the symptoms found in bronchitis.
In very rare cases, whooping cough can cause sudden unexpected death in babies.
In this stage, the patient starts showing signs of recovery. There are fewer bouts of coughing, which are also less intense. The recovery stage can take 3 or more months. Even in this stage, the patient can experience bouts of intense coughing.
Causes of whooping cough
Whooping cough is a bacterial infection caused by Bordetella pertussis. Infection occurs in the lining of the airways, principally in the trachea (the windpipe) as well as the bronchi (airways that branch off from the trachea to the lungs).
As soon as Bordetella pertussis reaches the lining of the airways, it multiplies and paralyzes mucus-clearing components of the lining, causing an accumulation of mucus. As the mucus builds up, the patient tries to expel it by coughing; the coughing becomes more intense because there is so much mucus.
As inflammation of the airways gets worse (they swell up), they become narrower, which makes it harder to breathe and causes the "whoop" when the patient tries to get their breath back after a bout of coughing.
How does whooping cough spread?
People who are infected with Bordetella pertussis can transmit the infection to others from 6-20 days after the bacterium entered their body to 3 weeks after the start of the "whooping" cough.
The bacterium is transported in tiny droplets of water in the air. When the patient coughs and sneezes, hundreds of droplets of moisture are expelled into the air.
If people nearby inhale some of this moisture, they are exposed and could become infected.
Prevention and vaccines for whooping cough
Prevention of whooping cough is key. If a family member is infected, it may be recommended that other family members be treated with antibiotics.
The pertussis vaccine
The pertussis vaccine prevents whooping cough.
For the general population, the pertussis vaccine is available to prevent the illness; the DTaP vaccine protects against diphtheria, tetanus, and pertussis.
As part of the recommended immunization schedule, it is given to infants and children in a series of five injections.
It is vital that pregnant mothers, as well as those who are in close contact with infants (newborns and babies up to 12 months of age), be vaccinated against pertussis.
Whooping cough affects approximately 48.5 million people every year, of these, 295,000 will die. According to WHO (World Health Organization), pertussis is one of the leading causes of vaccine-preventable deaths globally. The majority of cases (over 90 percent) occur in low- and middle-income countries.
Children of parents who will not let them be vaccinated are 23 times more likely to develop whooping cough compared with fully immunized children, researchers reported in the journal Pediatrics.
Tests and diagnosis of whooping cough
During its early stages, misdiagnosis is common, because the signs and symptoms are similar to those found in other respiratory diseases, such as bronchitis, the flu, and the common cold.
Doctors can usually diagnose whooping cough by asking questions regarding symptoms and listening to the cough (the whooping cough sound stands out).
The following diagnostic tests may be ordered:
- A throat or nose culture test - the doctor or nurse takes a swab or suction sample, which is sent to the lab and checked for the presence of the Bordetella pertussis bacterium.
- Blood tests - the doctor may want to know what the white blood cell count is. If it is high, it means there is probably some kind of infection.
- Chest X-ray - the doctor may want to see whether there is any inflammation or fluid in the lungs.
If whooping cough is suspected in an infant, they may need to be diagnosed in a hospital.
Treatments for whooping cough
Infants are usually admitted to hospital for treatment because, for that age group, pertussis is more likely to lead to complications. Intravenous infusions may be required if the child is unable to keep fluids or food down. The infant will be placed in an isolation ward to make sure the disease does not spread.
Older children, adolescents, and adults can usually be treated at home.
Antibiotics are given to kill the bacterium Bordetella pertussis, and to help the patient recover faster. Antibiotics might be prescribed for household members too. Antibiotics also stop the patient from being infectious within 5 days of taking them.
If pertussis is not diagnosed until the later stages, antibiotics will not be given, because, by then, the bacteria have gone.
Corticosteroids - prescribed if the child has severe symptoms; these are administered together with antibiotics. Corticosteroids are powerful hormones (steroids) that are very effective at reducing inflammation in the airways, making it easier for the child to breathe.
Oxygen - may be given through a facemask if additional help with breathing is needed. A bulb syringe may also be used to suction away mucus that has built up in the airways.
Treatment for the cough - OTC (over-the-counter) cough medications are ineffective at relieving the symptoms of whooping cough, and doctors advise against their use. Unfortunately, there is not much that can be done about the cough. Coughing helps bring up phlegm that accumulates in the airways.
Measures you can take at home
For older children and adults, symptoms are usually less severe. The doctor may advise that the patient get:
- Plenty of rest.
- Consume plenty of fluids to prevent dehydration.
- Try to keep excess mucus and vomit cleared from the airways and the back of the throat to prevent choking.
- Tylenol (acetimophen, paracetamol) or ibuprofen to relieve sore throat and reduce a fever. Do not give aspirin to children under 16.
Complications of whooping cough
Older children and adults - the majority of patients recover from pertussis with no complications or problems. In most cases, complications are caused by the strain of coughing so much and so intensely, and may include:
- a swollen face
- abdominal hernias
- broken blood vessels in the sclera (whites of the eyes)
- cracked or bruised ribs
- mouth and tongue ulcers
- otitis media (middle-ear infection)
Infants and young children are much more susceptible to serious complications from whooping cough, including:
- severe dehydration
- fits (seizures)
- hypotension (low blood pressure)
- kidney failure
- weight loss if they vomit excessively
Temporary pause in breathing - if breathing difficulties are severe, there is a risk of brain damage due to oxygen deprivation (extremely rare).
Pregnant mothers, people with a reduced immune system, and people with diabetes are more at risk of complications.