Pertussis, also known as whooping cough, is a highly contagious disease caused by a bacterium named Bordetella pertussis. Pertussis causes a severe cough with little or no fever.

The cough can become severe enough to cause vomiting or gagging. Some of those infected make a “whooping” sound when they breathe in after coughing, thus the name “whooping cough.” However, not all children, especially infants, make this sound.

Many adults believe pertussis disappeared with polio and diphtheria; however, the incidence of pertussis has gradually increased since the early 1980s. Before the availability of the pertussis vaccine in the 1940s, more than 200,000 cases of pertussis were reported annually.

While immunization programs have been successful in reducing the incidence of the disease in children and infants, waning immunity in adolescents and adults can allow the transmission of the disease to unimmunized infants.

Reported cases of the disease are at a 40-year high. The cause of the increase is not clear. Anyone can get pertussis, but young children, particularly unvaccinated or incompletely vaccinated infants less than one year old, are most at risk.

Symptoms of pertussis usually appear 5-21 days after exposure to an infected person. Throughout the course of the disease, fever is minimal. The course of the disease is divided into three stages by medical professionals.

Stage one, called the catarrhal stage, usually starts with symptoms resembling a common cold, such as a runny nose, headache, sneezing, low-grade fever and a mild, occasional cough. The cough gradually becomes more severe and after 1-2 weeks, the second stage begins.

Stage two, called the paroxysmal stage, is when the diagnosis of pertussis is suspected. The patient has bursts (or paroxysms) of numerous, rapid coughing fits. At the end of the paroxysm, a long inhalation is accompanied by a high-pitched whoop.

During such an attack, the patient may turn blue. Children and infants in particular appear very ill and in distress. Vomiting and exhaustion commonly follow these episodes. The child usually appears normal between attacks.

Paroxysmal attacks usually occur more frequently at night, averaging 15 attacks per 24 hours. During the first or second week in this stage, the attacks occur more frequently, remain at the same level for 2-3 weeks, then gradually decrease.

The paroxysmal stage usually lasts 1-6 weeks, but may persist up to 10 weeks. Infants younger than six months old may not have enough strength to make a whooping sound, but they still have the paroxysms of coughing.

During the third stage, called the convalescent stage, there is a gradual recovery. The cough becomes less paroxysmal and disappears in 2-3 weeks, however, paroxysms often recur with subsequent upper respiratory infections. These paroxysms can occur many months after the onset of the initial pertussis infection.

Infants are at highest risk for acquiring pertussis-related complications. The most common complication--and the cause of most pertussis-related deaths--is bacterial pneumonia. Neurological complications, such as seizures, also can develop as a result of the low oxygen level to the brain that may occur during the fits of coughing.

Other complications, such as ear infections, lack of an appetite, and dehydration, can occur. In addition, pressure effects, such as a collapsed lung, nosebleed, bleeding into the brain, and hernia can develop during paroxysmal coughing.

Antibiotics may make the illness less severe if started early. If a person is exposed to pertussis, specific antibiotics may help prevent the disease, so parents should consult a physician if exposure is suspected. Caring for Our Children, National Health and Safety Performance Standards: Guidelines for Out-of-Home Child Care, 2nd Edition, states the infected child is to be excluded from childcare until five days of appropriate antibiotic treatment is completed.

The bacteria that cause pertussis are found in the mouths, noses, and throats of infected people. Pertussis, like many other respiratory diseases, is spread by droplet spray from the mouth and nose when an infected person coughs, sneezes, or speaks and then enters an uninfected person’s respiratory tract.

Pertussis is highly contagious. In a household, 70-100 percent of those exposed to the bacteria will become infected while 50-80 percent of those exposed in a school setting will contract pertussis.

Pertussis is generally preventable through proper immunization. Unimmunized or inadequately immunized people are at the highest risk of becoming infected with pertussis. Although immunization may not be 100 percent effective, it significantly reduces the severity of the disease.

Childcare providers should make sure that all children under their care are properly immunized against pertussis. The vaccine is called DTaP which includes vaccines for dyptheria, typhoid, and pertussis, and all children should have five doses by the time they are 7 years old.

The immunizations are usually given at 2, 4, 6 and 15-18 months old, and another between 4-6 years old; however, each state will have its own immunization schedule.

Side effects of the vaccine are minimal; about 25 percent of children may get a fever along with a little redness and soreness at the site of the injection. About one-third of the children may have some fussiness after the injection.

These are all normal reactions, and the parent or health care worker should keep the child well-hydrated. Parents may ask their child’s physician about giving medication such as acetaminophen or ibuprofen if needed.

Adults ages 19-64 may receive a “catch up” booster immunization if any doubt exists that the person received the full complement of immunizations as a child. New adult- and adolescent-formulated combination diphtheria, tetanus toxoid and pertussis (DTaP) vaccines will soon be available in the U.S.

Any person diagnosed with pertussis should stay home and avoid contact with others until they have been on appropriate antibiotics for five days. Those exposed to a person with a known case of pertussis should contact his or her health care provider. The exposed person may receive a pertussis booster injection and may be put on a short course of antibiotics to prevent the disease.

Pertussis can be a deadly disease; but armed with the knowledge and by taking proper action, childcare providers can help prevent serious problems with those under their care.

Joe Knight
Family Practice Physician Assistant and medical writer, Fresno, California

Centers for Disease Control and Prevention, www.cdc.gov/vaccines/pubs/pinkbook/downloads/pert.pdf

Mayo Clinic, www.mayoclinic.com/health/whooping-cough/DS00445

National Association of Nurse Practitioners, www.pertussis.com

Immunization Action Coalition, 1573 Selby Ave., Ste. 234, St. Paul, MN 55104; 651-647-9009; www.vaccineinformation.org/video/pertussis.asp