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Learn About Pertussis

Pertussis, also known as whooping cough, is an extremely contagious respiratory infection caused by the bacteria, Bordetella pertussis. It can be especially serious and even fatal for infants. Unfortunately, many people who spread it may not know they have it. Infection can occur throughout the year, but in North America, its activity peaks in summer and fall. The classic sign of pertussis is a "whooping" sound made at the end of an episode of violent coughing, giving the common name of "whooping cough." The Chinese name for pertussis is "the 100-day cough," which describes the duration of illness, since it often lasts up to 3 to 6 months.

Key Facts

  • Very contagious respiratory infection caused by bacteria known as Bordetella Pertussis.
  • Most commonly occurs in preschool/school-age children, though can infect any age group.
  • Most serious and potentially fatal in infants.
  • Usually starts with cold-like symptoms followed by persistent harsh cough and a whooping sound.
  • Gradually resolves over 3 to 6 months, regardless of therapy.
  • Pertussis is preventable by vaccination. Routine childhood vaccinations greatly reduce the likely of infection in infants and children.
  • Immunity decreases with age. It is recommended that all adults age 19-65 get at least one "booster" vaccination.
  • Older adults should also get a "booster" vaccine if they come into contact with babies less than 12 months old.

What Is Pertussis?

Pertussis is a respiratory tract infection caused by the bacteria Bordetella pertussis.

It most commonly occurs in preschool and school-age children but can occur at any age. The illness typically starts 7 to 10 days after being exposed to an infected person. One usually presents with mild upper respiratory symptoms (nasal drainage, tearing, mild cough and tiredness), similar to the common cold. This stage is often referred to as the catarrhal stage.

After 1 to 2 weeks, the illness progresses from a mild cough into the second stage of coughing paroxysms (persistent and prolonged rapid coughing spells). This stage is called the paroxysmal stage.

The paroxysmal stage is categorized by coughing spells that often result in vomiting and is followed by a whooping sound. During a coughing spasm, there the neck veins may pop out, eyes bulge and the tongue stick out. The person may even appear blue around the mouth and face.

How often these paroxysmal, or coughing, episodes occur may vary. There can be several per hour to 5 to 10 per day. The episodes are often worse at night and can interfere with sleep. This stage can last up to 3 months. The symptoms of cough gradually improve over weeks to months. This stage is often referred to as the convalescent stage.

For 6 to 12 months following the illness, viral infections may be associated with a reappearance of the paroxysmal cough.

How Pertussis Affects Your Body

Initially, the individual will tend to have a runny nose, tearing eyes, mild cough and general tiredness. This resembles the symptoms of a common cold, and may be ignored at first.  Later, there may be severe coughing spells, a whooping sound, and vomiting. An individual may experience light-headedness or headaches from harsh coughing. The lips and areas around the lips may even turn blue immediately after a coughing spell. Weight loss may occur as persistent coughing interferes with eating. A fever is typically not seen. If there is fever, there may be an associated bacterial infection.

How Serious Is Pertussis?

Pertussis is the most severe in the first 6 months of life and in preterm or unimmunized infants. Almost all deaths and over 80 percent of hospitalizations associated with pertussis have been in infants less than 3 months of age. Children under 6 months of age usually experience a shorter respiratory symptom phase is shorter and the infant may gag or gasp, or even stop breathing temporarily. Often, at times, there is no whooping and the recovery is longer.

In preschool children, pertussis can be exhausting, given the length of course. Complications, including rib fractures, can result. In some older children and adults, the cough doesn't happen in fits and doesn't have a whopping sounds. Vomiting with cough is the best predictor of pertussis as the cause of prolonged cough in adults.

More severe complications may occur in infants, including pneumonia, heart failure, collapsed lung, brain bleeds and death.

    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.

    Page Last Updated: March 13, 2018

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