Whooping Cough (Pertussis)

Whooping cough is one of the most common vaccine-preventable infectious diseases among children younger than 5

Whooping cough is an infectious bacterial illness that affects the respiratory passages. First described in the 1640s, whooping cough got its name due to its spasms of coughing that is punctuated by a characteristic high-pitched "whoop" sound when the child inhales deeply after a coughing spell.

• Whooping cough is one of the most common vaccine-preventable infectious diseases among children younger than 5 years of age in the United States. Whooping cough is another name for pertussis—the "P" in the familiar DTaP (diphtheria, tetanus, and acellular pertussis vaccine) combination inoculation routinely given to children and the "p" in Tdap given to adolescents and adults.
• Despite the widespread use of pertussis vaccines, whooping cough has made a comeback in recent years. According to the U.S. Centers for Disease Control and Prevention (CDC), prior to the introduction of the pertussis vaccine, there were an average of 175,000 cases of whooping cough each year. This dropped off to fewer than 3,000 cases per year in the 1980s. There has been a recent resurgence in the U.S., with a total of 48,277 cases of pertussis reported in 2012, 24,231 cases in 2013, and 32,971 cases in 2014.
• The World Health Organization estimates there were 195,000 deaths from whooping cough worldwide in 2008 and 139,382 reported deaths in 2011, making this easy-to-prevent infectious disease one of the leading causes of illness and death.
• The prevalence of whooping cough in infants and children is increasing. Most deaths from pertussis occur among infants under 3 months of age. The incidence rate of pertussis among infants is greater than in all other age groups. The second highest rates of whooping cough occur in children 7 to 10 years of age.
• A pertussis epidemic arose in June 2014 in California, and as of Nov. 26, 2014, the California Department of Public Health had received 9,935 cases of pertussis.
• States that reported pertussis epidemics in 2012 include Washington (4,783 reported cases), Vermont (632 reported cases), Minnesota (4,433 reported cases), Wisconsin (5,923 reported cases), and Colorado (1,510 cases).

The course of whooping cough follows three stages.

• Stage 1: The first stage of whooping cough is the catarrhal (runny nose) stage. This phase typically lasts for 1-2 weeks. Symptoms during this phase resemble that of an upper respiratory illness or common cold: runny nose, nasal congestion, sneezing, and occasional cough. A low-grade fever may be present in some cases. It is only during this stage that antibiotics can halt the progression of whooping cough.
• Stage 2: The second stage of whooping cough is the paroxysmal stage. The duration of this phase is highly variable, lasting from 1-10 weeks. Intense and drawn-out bouts of coughing characterize this phase. The attacks tend to be more frequent at night, with an average of 15 attacks in a 24-hour period. Often people can hear a high-pitched "whoop" caused by the gasping person inhaling between coughs. (Barking coughs usually indicate a viral infection and are not indicative of whooping cough). Newborn babies and infants, in particular, may appear to stop breathing and perhaps turn blue during the coughing spasms. Vomiting or choking is also common during this stage as well.
• Stage 3: The third stage of whooping cough is the convalescent stage. This can last for weeks or months and a chronic cough that becomes less paroxysmal (fewer sudden outbursts of coughing) in nature characterizes this stage.

For children, follow the recommended vaccine schedule for the DTaP (diphtheria, tetanus, pertussis) inoculations. Physicians administer age-appropriate shots to children at the ages of 2 months, 4 months, 6 months, 15-18 months, and 4-6 years of age for full immunity, according to the American Academy of Pediatrics; however, vaccine immunity generally wanes after six to 10 years and does not result in permanent immunity, which is why a pertussis booster shot is needed.

• In 2005, the U.S. government approved Tdap, the first pertussis booster shot for children 10-18 years of age. The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control recommends one dose of Tdap in place of one Td booster.
• For adults 19 and older, the ACIP recommends a single dose of Tdap.
  • If you have never received a dose of Tdap, one dose of Tdap should replace one dose of Td for booster immunization if the most recent tetanus toxoid-containing vaccine was received at least 10 years earlier.
  • Adults over 19 years of age in close contact with, or anticipating contact with, infants aged 12 months or younger or with pregnant women, who have not previously received Tdap should receive a dose of Tdap; an interval as short as two years since the most recent Td is suggested.
  • Healthcare personnel in settings with direct patient contact who have not previously received Tdap should receive a dose of Tdap; an interval as short as two years since the most recent Td is recommended.
  • The CDC recommends pregnant women receive Tdap before pregnancy. Recommendations in 2011 from the CDC added that pregnant women who have not been previously vaccinated with Tdap should get one dose of Tdap during the third trimester or late second trimester—or immediately postpartum, before leaving the hospital or birthing center.
  • The vaccine side effects are mild but can include tenderness, redness, a lump at the site of the injection, and fever.

The bacteria Bordetella pertussis causes whooping cough. Humans are the only known reservoir for these bacteria. (That means it can only thrive and multiply in humans.)

• Whooping cough spreads by contact with droplets coughed out by someone with the disease or by contact with recently contaminated hard surfaces upon which the droplets landed. The B. pertussis bacteria thrive in the respiratory passages where they produce toxins that damage the tiny hairs (cilia) needed to remove particulate matter and cellular debris normally introduced into the airways with each breath. This results in increased inflammation of the respiratory passages and the typical dry cough that is the hallmark of the infection. Whooping cough is contagious from 7 days after exposure to the bacteria and up to 3 weeks after the onset of coughing spasms. The most contagious time is during the first stage of the illness.
• Initially thought to be a disease of childhood, studies have shown that adults are susceptible to whooping cough and account for up to 25% of cases. The disease tends to be milder in adults and adolescents—a persistent cough much like an upper respiratory infection or common cold. Because of this fine distinction, physicians frequently miss a diagnosis of whooping cough in that population and thus allow the bacteria to spread to more susceptible infants and children.
• Whooping cough is highly contagious. Between 75%-100% of unimmunized household contacts of a person with pertussis will develop the disease. Even among fully immunized and naturally immunized people living in the same household, there have been reports of undetectable infection following extreme exposure.
• Risk factors for getting whooping cough include exposure to an infected person's coughing or sneezing or touching surfaces used by an infected person. Both frequent hand washing and the use of masks will help lessen the likelihood that the bacteria will spread to other members of a household where someone has whooping cough. Also, avoid touching your nose or mouth and introducing the bacteria you may have picked up during outbreaks.
• A related bacterium Bordetella parapertussis causes a similar but less severe cold-like infection called parapertussis.

When to call the doctor

• If you suspect you or your child has whooping cough
• If your child has exposure to someone with whooping cough, regardless of whether the child has received immunization shots
• If your child has a fever that cannot be controlled with over-the-counter medication
• If your child is unable to keep solids and liquids down (vomits)

When to go to the hospital

• If your child stops breathing, call 911 emergency services and begin CPR.
• If your child turns blue during a coughing spell
• Go to a hospital's emergency department if someone with whooping cough shows these symptoms:
  • Inability to tolerate liquids (vomiting)
  • Uncontrolled fever even with anti-fever medications
  • Signs of respiratory distress including rapid breathing and turning blue
  • Signs of dehydration, including weight loss, dry mucous membranes, or decreased urine output

The best way to diagnose whooping cough is by confirming the presence of the specific disease-causing bacteria Bordetella pertussis in mucus taken from the nose and throat.

• Culture test: Because the growth of the bacteria is inhibited by cotton, swabs made from special material, either calcium alginate or Dacron, must be used in obtaining the sample. Studies have shown that cultures are more likely to be positive if medical professionals collect the sample during the first stage of the illness or early in the second. The likelihood of isolating the organism (and confirming the diagnosis) declines with any delay in specimen collection beyond the first three weeks of illness. A culture for Bordetella pertussis is usually negative after 5 days of treatment with antibiotics.
• Serologic testing and PCR: Other laboratory methods used to diagnose pertussis infection such as serologic testing and PCR are available in certain labs. Neither method is more specific than the culture isolation of the organism.
• Blood test: A healthcare provider may perform a complete blood count (CBC).

Because younger children are at higher risk to develop a life-threatening or severe case of whooping cough than adults, many may be admitted to the hospital.

For children and adults who do not require hospitalization, here are some tips to manage the disease at home after a doctor has diagnosed whooping cough.

• Isolate the person as much as possible (for example, in a separate bedroom) until he or she has received five days of antibiotics. If possible, everyone who encounters the sick person should wear a surgical mask to cover their face to limit the spread of pertussis. Sometimes doctors may prescribe antibiotics to close contact with an individual diagnosed with whooping cough to prevent transmission of the bacteria.
• Practice good hand washing. Whooping cough bacteria spreads through contact with contaminated inanimate objects such as dishes.
• Drink plenty of fluids, including water, juices, and soups, and eat fruits to prevent dehydration.
• Eat small, frequent meals to decrease the amount of vomiting.
• Use a cool-mist vaporizer to help loosen secretions and soothe the cough.
• Keep the home environment free from irritants that can trigger coughs, such as smoke, aerosols, and fumes.
• Monitor a sick child for signs of dehydration, such as dry lips and tongue, dry skin, decrease in the amount of urine or wet diapers, and crying without producing tears. Report any signs of dehydration to your doctor immediately.
• Do not give cough medications or other home remedies unless otherwise instructed by your doctor.

Antibiotics lessen the severity of whooping cough and make the person taking them noncontagious. Antibiotics are most effective if given early in the first phase of the illness.

The Sanford Guide to Antimicrobial Therapy recommends the following antibiotic treatments: a 5-day course of azithromycin, a 7-day course of clarithromycin, or a 14-day course of either erythromycin or trimethoprim/sulfamethoxazole (TMP/SMX).

• Some strains of whooping cough are resistant to certain antibiotics. Symptoms may worsen if this is the case.
• In addition to treating the adult or child who has whooping cough, everyone in the household should receive prophylactic antibiotic treatment.
• All close contacts younger than 7 years of age who have not completed their primary vaccinations (including the DTaP vaccine to prevent pertussis spread) should complete this series with the minimum time between shots.
• Close contacts younger than 7 years of age who have completed their primary series but have not received a booster of DTaP, or the whooping cough vaccine, within 3 years of exposure should get the booster dose.
• Exposed adults should get the Tdap vaccine (see the "Prevention" section below).
• Anyone with whooping cough should be isolated for 5 days after starting antibiotics or until 3 weeks after the onset of the coughing spasms if the person has not received antibiotic treatment.

Notify schools and daycare facilities of whooping cough illnesses. Healthcare providers should evaluate children who later develop a cough. Children younger than 7 years of age who attend school or daycare and are behind in their vaccinations should receive them. Your healthcare provider should report cases of whooping cough to the local health department.

• Medical professionals do not recommend school-wide treatment with antibiotics.
• Children with mild cases of whooping cough may return to school or daycare after receiving antibiotics for at least 5 days.

Complications of whooping cough most commonly appear in children younger than 1 year of age, with an increased risk of severe whooping cough in premature infants.

• Between 1999-2003, 17,000 children under 2 years of age diagnosed with whooping cough required hospitalization.
• More than half of infants younger than 1 year of age who get the disease must be hospitalized.
• In 2012, medical professionals reported 18 deaths due to whooping cough to the CDC; the majority of them were infants under 3 months of age.
• Bacterial pneumonia is the most common complication of whooping cough. It is also the most common cause of pertussis-related deaths. The CDC estimates about 1 in 5 infants with pertussis get pneumonia (lung infection).
• Other complications include:
  • bluish skin from lack of oxygen, 
  • lung collapse,
  • sinusitis,
  • otitis media (ear infection),
  • dehydration,
  • nosebleed,
  • bruising,
  • hernias,
  • retinal detachment,
  • rectal prolapse,
  • seizures,
  • diseases of the brain, and
  • failure to thrive.