Infection: Whooping Cough
Infection: Whooping Cough
Whooping cough is a highly contagious and potentially fatal bacterial infection of the upper respiratory tract.
Whooping cough, or pertussis, is a potentially severe upper respiratory infection characterized by spells of intense coughing that end in a whooping sound when the person is finally able to catch their breath. It can affect people in any age group, but is most common (and most serious) in infants and young children. The organism that causes whooping cough affects only humans; it is not spread by animals.
The early symptoms of whooping cough resemble those of the common cold—runny nose, sneezing, general unwell feeling—and the disease is often mistaken for an ordinary cold. After about a week of cold-like symptoms, however, the patient develops episodes of severe coughing that can bring up thick phlegm (mucus) from the throat. The coughing may be intense and spasmotic enough to cause vomiting or cause the patient to turn red or blue in the face. At the end of the coughing attack, the patient may make a whooping or crowing sound as they gasp to take in their next breath of air.
At one time whooping cough was a leading cause of death in infants and toddlers, causing 3,000 to 5,000 deaths in the United States
every year. Even though vaccines against whooping cough have been available since the 1940s, the disease is still one of the leading causes of vaccine-preventable deaths worldwide. The World Health Organization (WHO) estimates that there are between 30 and 50 million cases of pertussis each year around the world, and 300,000 deaths. Ninety percent of cases of whooping cough occur in the developing world. Widespread vaccination against the disease, however, has lowered the death rate in the United States to fewer than thirty cases per year.
In the United States, cases of whooping cough tend to cluster in cycles, with peaks every three to four years. Outbreaks of whooping cough are seasonal, with most cases occurring between June and September. On average there are about 2.7 cases of whooping cough per 100,000 in the general population in North America.
Most people who get whooping cough in the United States are unimmunized children or older teenagers and adults whose full immunity has faded. The classic symptoms of whooping cough are not often seen in this latter group, who are likely to have cough for more than three weeks. According to the Centers for Disease Control and Prevention (CDC), 29 percent of patients with whooping cough are younger than one year; 12 percent are aged one to four years; 10 percent are aged
five to nine years; 29 percent are aged ten to nineteen years; and 20 percent are older than twenty years.
Whooping cough is caused by a bacterium known as Bordetella pertussis, an organism that appears to live only in humans. The organism is spread primarily by droplets in the coughing of infected individuals. When someone breathes in some of these droplets, the bacterium attaches itself to the tissues that line the throat and upper respiratory tract and multiplies. The patient usually begins to feel sick within three to twelve days after being infected.
Opposition to Vaccination
Since the early 1990s public health doctors have become increasingly concerned about a growing trend among parents in some parts of the United States to refuse to have their children vaccinated against whooping cough and other childhood diseases. Most of these parents are too young to remember when such diseases as smallpox, polio, diphtheria, and whooping cough were real threats to children's lives, but because they have heard rumors that vaccines can cause such disorders as autism and multiple sclerosis, they choose not to have their children vaccinated. They think that the risks of side effects from the vaccine are greater than the risks that their children will get a potentially life-threatening disease.
The problem is that when the rate of vaccination in a community drops below a certain point, diseases that were once rare begin to make a comeback. In parts of Colorado the rate of whooping cough has nearly doubled since the mid-1990s. Over the long term, the children who are not vaccinated are likely to come down with a serious illness themselves as well as putting others in their communities at risk. It may take a major outbreak of whooping cough or another vaccine-preventable disease to change some parents' minds about the benefits of vaccination.
The symptoms of whooping cough depend on the stage of the illness:
- Early phase (lasts one to two weeks). The patient appears to have an ordinary cold, with runny nose, sneezing, and nasal congestion. There may be low-grade fever and runny eyes. The disease is most likely to be spread to others at this stage.
- Coughing stage (one to two weeks). The patient has spells of intense coughing that may last for several minutes and end in a whooping sound as the child struggles for breath. Infants younger than six months do not usually make the whooping sound but may become completely exhausted. The child may turn red in the face and vomit at the end of the coughing spell. Adults with whooping cough may get headaches during this stage. The coughing is usually worse at night. In some cases the patient develops pinpoint-sized red marks in the upper chest or the whites of the eyes caused by the breaking of tiny blood vessels during the coughing spells. These little marks are called petechiae.
- Recovery stage (one to two weeks). The child begins to feel better but continues to cough occasionally.
In most cases the doctor will make the diagnosis on the basis of the patient's physical symptoms, a history of exposure to others with whooping cough, and the patient's record of immunization against whooping cough. The doctor may take a blood test to see whether the patient has a higher than normal number of lymphocyte white blood cells or order a chest x ray to see whether the patient has developed pneumonia, but neither of these tests is specific for whooping cough. To make the diagnosis definite, the doctor can take a sample of fluid from the patient's nose or throat on a cotton swab and send it to a laboratory for analysis.
Treatment of whooping cough depends partly on the patient's age and partly on the severity of the disease. Infants younger than six months often need hospitalization so that they can be given oxygen, have mucus removed from their airway, and fed intravenously if necessary. Very young infants are at greatest risk of ear infections, seizures, or other complications of whooping cough.
Older children, teenagers, and adults should stay home from school or work in order not to give the disease to other people. They should rest in bed if at all possible. In most cases the doctor will prescribe an antibiotic medication, usually for two or three weeks. Antibiotics can shorten the duration of the illness and also shorten the length of time that the patient is contagious. In some cases the doctor will prescribe antibiotics for other members of the patient's family to reduce their risk of getting the disease.
Over-the counter cough medicines are not usually very helpful in relieving the sore throat and coughing spells of whooping cough. A cool-mist vaporizer and drinking lots of fluids are usually more effective.
Older children, adolescents, and adults usually recover from whooping cough in five to six weeks without any lasting effects. Infants who have not been immunized against whooping cough and older adults with heart
problems or lung disease are at greatest risk of developing pneumonia or other complications of whooping cough. About two-thirds of infants who develop whooping cough will need hospital treatment; the average length of stay for a baby with whooping cough in 2004 was seven days. Of the deaths caused by whooping cough in the United States in the early 2000s, 99 percent were in infants.
The best protection against whooping cough is immunization. Since the 1940s, the vaccine that protects against pertussis has been combined with vaccines against diphtheria and tetanus in a single vaccine. The American Academy of Pediatrics (AAP) recommends a total of five doses of the combined vaccine in children between the ages of two months and six years. Neither the vaccine nor getting the disease confers permanent immunity against whooping cough, however; the effectiveness of the vaccine fades away in three to five years after the last shot.
Because an increasing number of cases of whooping cough are being diagnosed in teenagers, in 2005 the AAP recommended that all teenagers receive an additional booster shot of vaccine. This measure is intended to protect younger children as well as the adolescents, because the evidence indicates that many cases of whooping cough in infants are caused by the infection being transmitted to them by older family members. For adults less than sxity-five years of age, one booster of whooping cough vaccine should be given combined with the once every ten years tetanus/diphtheria booster. This is especially important in prospective parents and grandparents and those health care workers who work in pediatrics.
Whooping cough is likely to be a major public health problem even in developed countries for the foreseeable future because of some people's opposition to vaccination. In the 1970s there were a number of lawsuits filed by people who felt that they had been injured by the diphtheria/tetanus/pertussis vaccine. While it was not clear in many of these cases that the person's health problems were caused by the vaccine, Congress passed a law in 1986 that requires doctors to give a child's parents an information sheet about a vaccine before giving the child the shot. The doctor is also required to report any side effects of the vaccination to a national reporting system.
Vaccines licensed for use in the United States must go through a three-stage process of clinical trials that often takes ten years or even longer before the new vaccine is approved. A newer form of the diphtheria/tetanus/pertussis vaccine was developed in 1991 and replaced the older vaccine completely by 2002. It is reported to have lowered the rate of side effects from vaccination in the United States by 90 percent.
SEE ALSO Common cold; Tetanus
WORDS TO KNOW
Pertussis: The medical name for whooping cough.
Petechiae: Tiny reddish or purplish spots in the skin caused by the breaking of small blood vessels during intense coughing or vomiting.
Phlegm: Thick mucus secreted in the throat and lungs during an upper respiratory infection.
Laskey, Elizabeth. Whooping Cough. Chicago, IL: Heinemann Library, 2003.
Allen, Arthur. “Bucking the Herd.” Atlantic Monthly, September 2002. Available online at http://www.theatlantic.com/doc/200209/allen_a (accessed April 22, 2008). This is an article about the reappearance of whooping cough in Colorado as the result of parents' opposition to vaccination.
American Academy of Family Physicians (AAFP). “Whooping Cough: What You Should Know.” American Family Physician 74 (August 1, 2006): 427. Available online at http://www.aafp.org/afp/20060801/427ph.html (accessed April 22, 2008).
Centers for Disease Control and Prevention (CDC). History of Vaccine Safety. Available online at http://www.cdc.gov/vaccinesafety/basic/history.htm (updated February 26, 2008; accessed April 22, 2008).
Centers for Disease Control and Prevention (CDC) Fact Sheet. Pertussis. Available online at http://www.cdc.gov/ncidod/dbmd/diseaseinfo/pertussis_t.htm (updated October 13, 2005; accessed April 22, 2008).
National Network for Immunization Information Fact Sheet. Important Facts for Parents to Know about the DTaP Vaccine. Available online in PDF format at http://www.immunizationinfo.org/assets/files/pdfs/2_DTAP_facts.pdf (updated October 2000; accessed April 21, 2008).
Nemours Foundation. Whooping Cough (Pertussis). Available online at http://www.kidshealth.org/parent/infections/lung/whooping_cough.html (updated December 2005; accessed April 22, 2008).