Myths and Facts: Pertussis

I n August, as kids were returning to school, educational districts throughout California sent health alerts to school administrators and parents about the growing rate of pertussis cases being reported in the state, and the front pages of local newspapers warned of a pertussis epidemic. As of Aug. 10, 2,774 cases of pertussis, also known as whooping cough, were reported to the California Department of Public Health (CDPH) — a sevenfold increase from the 395 cases reported through the same date in 2009. Of these reported cases, 159 (12 percent) had been hospitalized, the majority of whom were infants younger than 6 months old, and seven infants younger than 2 months old had died — none of whom had received any doses of pertussis-containing vaccine. And, the CDPH projected that if current trends continue, California will likely see more cases of pertussis than it has in more than 50 years and the highest rate of the disease in 47 years.¹

Yet, while California is the only state as of this writing to report an epidemic of pertussis, reporting of the disease can be spotty or delayed, according to Jeff Dimond, a spokesman for the Centers for Disease Control and Prevention (CDC).² And, with the peak season for pertussis starting in the summer, without intervention, the number of cases could potentially get much larger.

Lack of information is often the culprit behind the spread of this potentially dangerous disease. So, to avoid a future epidemic of this level, there is a serious need to distinguish between the myths and facts about what causes pertussis, how to treat it and, ultimately, how to prevent it.

Separating Myth from Fact

Myth: Pertussis is no longer common now that there is a vaccine to prevent it.

Fact: Pertussis was a leading cause of childhood illness and death in the U.S. in the first half of the 20th century. But, after the introduction of a vaccine, the number of cases reached a low in the mid-1970s. Since then, the incidence of pertussis has been increasing primarily among children too young to have completed the full course of vaccinations in teenagers, and in adults whose immunity has faded.³

In fact, periodic outbreaks of pertussis are not uncommon. The disease is endemic worldwide, and some 5,000 to 7,000 cases are reported in the U.S. in a normal year, according to the CDC. Epidemics occur every three to five years in the U.S., with the most recent in 2005, when there were more than 25,000 reported cases nationwide, and nearly 3,200 in California, where seven people died. 2 In countries where children aren’t routinely vaccinated, pertussis sickens 51 million and kills 600,000 people annually.⁴

Myth: Pertussis affects only children.

Fact: Pertussis affects people of any age. The disease was most common in infants and young children before vaccines were widely available. But, now that most children are immunized before entering school, the higher percentage of cases is seen among adolescents and adults.⁵ This is because the vaccine children receive eventually wears off, leaving most teenagers and adults susceptible to the infection during an outbreak. Still, children are a high-risk population for infection. Because they aren’t fully immune to pertussis until they’ve received at least three shots, those 6 months and younger are at greatest risk of contracting the infection.⁶

In the current epidemic occurring in California, however, there is a high incidence of pertussis in Hispanic infants (all of the fatalities have been Hispanic). According to Dr. Gilberto Chavez, deputy director of the CDPH’s Center for Infectious Disease, lack of information and inoculations in agricultural regions in the state’s Central Valley, home to many Latino farmworkers, might be a culprit in the high incidence in this area.² In fact, cities in the CentralValley have the highest number of reported cases of pertussis.¹

Myth: Pertussis is an influenza-like viral infection.

Fact: Pertussis is not a viral infection; it is an upper-respiratory infection caused by the Bordetella pertussis or Bordetella parapertussis bacteria. It is easily spread from person to person, which happens when an infected person sneezes or coughs and tiny droplets containing the bacteria move through the air and are breathed into the lungs of anyone who happens to be in the vicinity. The bacteria then multiply in the airways and produce toxins that interfere with the respiratory tract’s ability to get rid of the germs, causing the development of thick mucus, as well as inflammation that narrows breathing tubes in the lungs.⁷

Myth: Pertussis is not a dangerous disease.

Fact: Pertussis is a serious disease that can cause permanent disability in infants and even death. Symptoms usually develop about a week after exposure to the bacteria, and severe coughing episodes start about 10 to 12 days later.In children, the coughing often ends with a “whoop” noise, caused when they try to take a breath after a coughing fit. However, the whoop noise is rare in patients under 6 months of age and in adults.⁵

Coughing spells, which can last from one to two minutes and often result in vomiting, severe facial congestions and a feeling or appearance of suffocation, happen as little as twice a day or as many as 50 a day. Between coughing attacks, the sufferer appears and usually feels perfectly well.⁸

Other pertussis symptoms include runny nose, slight fever (102 degrees Fahrenheit or lower) and diarrhea.While the outlook is generally very good in older children and adults, infants are at highest risk of death. Possible complications include pneumonia, convulsions, seizure disorders (permanent), nosebleeds, ear infections, brain damage from lack of oxygen, bleeding in the brain (cerebral hemorrhage), mental retardation, slowed or stopped breathing (apnea) or death.⁵

Myth: Doctors can easily diagnose whooping cough.

Fact: Because the symptoms of pertussis often mimic those of a cold, flu or bronchitis, many cases go undiagnosed. In addition, there is great variation in the severity and duration of the illness. Therefore, a key to clinical diagnosis is attacks of choking cough separated by long intervals of no coughing at all. Plus, diagnosis is often made only if the physician hears the cough. The website www.whoopingcough.net provides sound clips of children and adults with pertussis.⁸

When a diagnosis can’t be made by asking about symptoms or listening to the cough, medical tests may be needed to confirm the disease. These include a nose or throat culture and test, blood tests to check for high white blood cell counts, and a chest X-ray to check for the presence of inflammation or fluid in the lungs.⁹

Myth: Pertussis resolves in five to 10 days.

Fact: The initial stage of pertussis itself, when cold-like symptoms present, lasts between one and two weeks. The paroxysmal stage that follows with severe coughing spells lasts another two to four weeks. And, the convalescent stage of the disease, which is less severe, typically lasts between three and four weeks, but it can continue for months.⁴ In China, pertussis is known as the 100-day cough.

Myth: The pertussis vaccine does not adequately protect people from contracting the disease.

Fact: The pertussis vaccine is the best prevention against the disease if given as scheduled.It is often given in combination with vaccines against two other serious diseases, diphtheria and tetanus, and is known as the DTaP vaccine. Children should receive a series of five DTaP vaccines at ages 2 months, 4 months, 6 months, 15 to 18 months and 4 to 6 years. In addition, a booster shot, known as the Tdap vaccine, should be given to children at age 11 or 12 and then to all individuals every 10 years after that. Some healthcare organizations strongly recommend that adults up to the age of 65 receive the adult form of the vaccine against pertussis. Vaccine side effects may include fever, crankiness or soreness at the site of the injection. And, in rare cases, severe side effects can include persistent crying lasting more than three hours, high fever, and seizures, shock or coma.^5,10

In the case of a pertussis outbreak, children under age 7 who have not been immunized should not attend school or public gatherings, and should be isolated from anyone known or suspected to be infected for at least 14 days after the last reported case.⁴

Myth: Antibiotics are the treatment of choice for whooping cough at any stage in the disease.

Fact: In the initial stage of the disease, antibiotics are most effective in treating pertussis. However, most individuals are not diagnosed until the cough starts in the second stage of the disease, when antibiotics are less effective.⁴ Even so, antibiotics at this stage still can help reduce an infected individual’s ability to spread the disease to others. 5 Family members not yet infected also can be given preventive antibiotics.¹¹

Over-the-counter medications have little effect on whooping cough and are discouraged.What can help are fluids given through the vein if coughing spells are severe enough to prevent the person from drinking enough, and sedatives may be prescribed to young children. Infants younger than 18 months need constant supervision because their breathing may temporarily stop during coughing spells, and those with severe cases of pertussis should be hospitalized.⁵

Some lifestyle and home remedies also may be helpful for those dealing with coughing spells, including getting plenty of rest, drinking plenty of fluids, eating smaller meals (to avoid vomiting after coughing), vaporizing the room (to help soothe irritated lungs and loosen respiratory secretions), cleaning the air (to rid it of irritants that can cause coughing) and preventing transmission by covering a cough and washing hands often.¹²

Myth: The pertussis vaccine causes dangerous adverse reactions.

Fact: The first whole-cell pertussis vaccine, developed in the 1930s and in widespread use by the mid-1940s, was linked to some serious side effects. However, the whole-cell pertussis vaccine is no longer available. Today, the combined DTaP vaccine, licensed in 1991, is a more purified “acellular” version and produces fewer side effects. Getting pertussis, diphtheria or tetanus poses much more risk than getting the vaccine.^13,14

The risk of the DTaP vaccine causing serious harm or death is extremely small.¹⁴ Most children have no serious reactions from this combined vaccine. But, about 20 percent to 40 percent of children have some local reaction, such as pain, redness or swelling after the first three doses of DTaP, and after the fourth and/or fifth doses, these local reactions are more frequent. A temperature of 101 degrees Fahrenheit occurs in only 3 percent to 5 percent of children. More serious reactions, such as persistent crying, higher fever and febrile seizure, are rare and occur in fewer than one in 10,000 doses.¹³

There are some people who should not receive either the DTaP or Tdap vaccine, including those who have had a serious allergic reaction to a previous dose of either vaccine, or who have developed encephalopathy (brain injury) not due to another identifiable cause.In addition, someone with a recognized, possible or potential neurologic condition should delay receiving either vaccine until the condition is evaluated, treated and/or stabilized. While the vaccine does not cause neurological disorders, it can cause an already present underlying condition to show itself.¹³

Dispelling the Myths Now

With seven deaths in California caused by pertussis, the seriousness of preventing the disease can’t be overstated. While the pertussis vaccination is the most effective way to prevent the disease, history has shown that epidemics continue to occur. So, understanding what this disease is, its symptoms and how to treat them are just as important.