Pertussis, or whooping cough, was a common cause of childhood illness and death until the late 1940s, when an effective vaccine was introduced. During the next 30 years, the incidence of whooping cough fell dramatically. In the 1980s, pertussis began making a slow comeback, often infecting people who had been immunized. Today, most pertussis cases are diagnosed in people older than 10. Many adults with whooping cough recover within a few weeks, but some people's symptoms persist for months.
Early Symptoms Resemble a Cold
Bordetella pertussis, the bacterium that causes whooping cough, is a highly infectious organism that spreads from person to person via airborne droplets. After the bacteria enter your respiratory tract, they multiply and produce a toxin that is irritating to your airways. The first symptoms of pertussis -- a runny nose, watery eyes, sneezing and a mild cough -- begin 1 to 2 weeks after infection. Antibiotic therapy during this catarrhal stage might shorten the course of your illness, but many people dismiss their symptoms as those of a common cold and fail to seek medical attention. Treatment during later stages of pertussis helps prevent the spread of infection but does not shorten the course of the illness.
Toward the end of the catarrhal stage, which lasts 1 to 2 weeks, your cough will become more severe. While some adults with whooping cough only develop a nagging cough, others have the classic coughing paroxysms -- 5 to 10 forceful, rapid coughs -- followed by the hurried intake of air that causes the “whoop” of pertussis. Some people turn blue during a coughing paroxysm, and vomiting following a bout of coughing is not unusual. This paroxysmal stage of pertussis may last 6 weeks or longer.
As you enter the final convalescent stage of pertussis -- a stage that can last 2 to 12 weeks -- your coughing spasms gradually decrease in frequency and severity. You may have a temporary setback if you catch a cold or come in contact with something that irritates your airways. During this stage, your cough is triggered by the persistent airway inflammation caused by the pertussis toxin, rather than the bacteria themselves. Antibiotics, expectorants, decongestants and cough suppressants are unlikely to improve your symptoms during the paroxysmal and convalescent stages. Your doctor may prescribe a course of antibiotics to protect the people around you from infection.
Infants and young children are the most likely to develop pertussis-related complications, which include pneumonia, asphyxia, dehydration, brain damage, seizures and death. Although most complications and fatalities occur in infants under 1 year of age, pneumonia due to pertussis can be fatal at any age. And, even though most adults weather a bout of whooping cough without developing serious complications, vaccination is important in older people to prevent spreading it to infants and children.
The Chinese call pertussis “the 100-day cough,” which aptly describes its course in many adults. But the severity and duration of symptoms vary among people. Some people with partial immunity due to a previous vaccination may have shorter, milder courses. Others may cough persistently or intermittently for 4 to 6 months. Because neither vaccination nor infection confers lifelong immunity, much of the resurgence in pertussis among adults is attributed to waning immunity. This has led the Advisory Committee on Immunization Practices to recommend a 1-time booster vaccination for all adults. Ask your doctor if you should be immunized against pertussis.