What is whooping cough?

Whooping cough^[1], or pertussis, is a highly contagious respiratory tract infection. This infection is caused by bacteria known as Bordetella pertussis_ and causes uncontrollable, violent coughing.

Whooping Cough Symptoms

These coughing fits often make it hard to breathe and are followed by a sharp intake of breath that causes a “whooping” sound—hence the name “whooping cough.” Whooping cough was considered to be a childhood disease prior to the development of the pertussis vaccine^[2]. Whooping cough can be serious—even deadly—in babies younger than one year old. While it can affect people of all ages, pertussis now primarily affects children who are too young to receive the full course of whooping cough vaccines, as well as teens and adults with compromised or declining immune systems. Deaths associated with whooping cough are rare and most commonly occur in infants. That’s why is vital that pregnant women and other people who come into close contact with infants be vaccinated against the disease.

How common is whooping cough?

There are an estimated 24.1 million reported cases^[3] of pertussis per year. Of these, roughly 160,700 cases of pertussis result in death. According to the CDC, in 2012 (the most recent peak year for pertussis) there were 48,277 cases^[4] of whooping cough reported in the United States—the largest number since 1955. The number of cases of whooping cough in the U.S. has increased since the 1980s, while in 2010, the CDC saw an increase in reported cases among 7–10-year-old children.

Whooping cough symptoms

Early symptoms of whooping cough^[5] can last for 1–2 weeks. In time, the disease develops, and symptoms become more severe. Some coughing fits caused by pertussis infection can last for 10 weeks or more. This is why some people call whooping cough “the 100-day cough.”

Early-stage pertussis symptoms

Whooping cough usually begins with cold-like symptoms and may be accompanied by a mild cough or low-grade fever^[6]. While coughing in babies may be minimal or nonexistent, some babies may show a symptom called apnea, a pause in his or her breathing pattern. It takes about 7–10 days after infection for the signs and symptoms of pertussis to appear. Because these symptoms often resemble those of the common cold^[7], your healthcare provider may not immediately identify them as being caused by pertussis until more severe symptoms develop. The early symptoms of whooping cough can last for 1–2 weeks, and generally include:

• Runny nose
• Nasal congestion^[8]
• Red, watery eyes
• Low-grade fever (usually remains minimal throughout the duration of the illness)
• Mild, occasional cough
• Apnea (a pause in breathing) in babies

Late-stage pertussis symptoms

Between 1–2 weeks after the first symptoms of whooping cough appear, the disease progresses, and symptoms become more severe. Late-stage pertussis causes fits of multiple, rapid coughs brought on in response to the accumulation of thick mucus inside your airways. This coughing is characteristically followed by a high-pitched intake of breath and a “whooping” sound. The severe coughing fits that occur with pertussis can:

• Provoke vomiting (throwing up)
• Cause you to go red or blue in the face
• Cause extreme fatigue and exhaustion

While the “whooping” sound that accompanies the sharp intake of breath after coughing fits is what gives whooping cough its name, many people develop the cough without this characteristic sound. Despite the exhaustion that accompanies these coughing fits, you generally appear fairly well between fits. Coughing generally becomes more frequent and more severe as the illness progresses and can occur more at night than during the day. Generally, whooping cough is milder in teens and adults—especially those who have received the pertussis vaccine. The following symptoms can be a cause for concern in children:

• Vomiting
• Turning red or blue
• Seeming to struggle to breathe or having noticeable pauses between breaths
• Inhaling with a whooping sound

Recovery from whooping cough often takes time and happens slowly. Over time, the cough becomes milder and less frequent. However, other respiratory infections can cause coughing fits to return even months after the initial infection goes away. As with any illness, it is important that you contact your healthcare provider if you believe that you or your child has contracted whooping cough. Always let him or her know if you have any new or worsened symptoms, as he or she will be able to provide you with the proper diagnosis and appropriate course of treatment.

Whooping cough causes

Whooping cough is caused by an infection with the bacteria Bordetella pertussis. The transmission^[9] of whooping cough occurs when the bacteria are spread from an infected person to others (person-to-person contact).

Bordetella pertussis

Bordetella pertussis bacteria enter your body through your mouth, eyes, or nose. When someone infected with pertussis coughs or sneezes, tiny bacteria-laden droplets are sprayed into the air. You can catch whooping cough by inhaling these particles or by touching droplets left behind on surfaces touched by someone who is infected. The likelihood of catching whooping cough increases in crowded places like schools, daycare centers, public transportation, or workplaces. Because whooping cough is often spread through large groups of people in close contact, the beginning of the school year can present a higher risk of you or your child contracting the illness. If you think you or your child has pertussis, avoid going into public places and spreading the infection to others.

Risk factors for whooping cough

Because the whooping cough vaccine you receive as a child eventually wears off, most teens and adults are left susceptible to the infection during an outbreak. Because there continue to be regular outbreaks of whooping cough^[10] it's important that you and your children stay up-to-date on all pertussis vaccines. Babies younger than 12 months of age who are unvaccinated or who haven’t received the full course of recommended vaccines have the highest risk for severe complications and death.

Complications from whooping cough

Whooping cough can cause serious and, in some cases, deadly complications^[11] in babies and young children—especially if they have not received all recommended pertussis vaccines. Roughly half of babies younger than 1 year of age that catch whooping cough are hospitalized. The younger a baby is, the more likely that he or she will need to receive treatment in a hospital. According to the CDC^[12], of the babies hospitalized with whooping cough, approximately:

• 1 out of 4 (23%) get pneumonia (lung infection).
• 1 out of 100 (1.1%) will have convulsions (violent, uncontrolled shaking).
• 3 out of 5 (61%) will have apnea (slowed or stopped breathing).
• 1 out of 300 (0.3%) will develop encephalopathy (disease of the brain).
• 1 out of 100 (1%) will die as a result of the illness or associated complications.

Other serious complications of whooping cough in infants (especially those younger than 6 months old) include dehydration, weight loss, and seizures. Some teenagers and adults also develop complications as a result of whooping cough. These are usually less serious than those in babies and infants, however—especially after having received vaccination for pertussis. The cough itself often causes physical complications in teens and adults. For example, coughing fits may cause you to pass out or to fracture (break) a rib or break the blood vessels in the skin or whites of your eyes, if violent enough. In one study, less than 5%^[13](1 out of 20) of teens and adults with whooping cough needed hospitalized care. Of that 5%, 2% (1 out of 50) were diagnosed with pneumonia (lung infection) by healthcare professionals. The most common complications among teens and adults in another study were:

• Weight loss in 1 out of 3 (33%) adults
• Loss of bladder control in 1 out of 3 (28%)
• Passing out in 3 out of 50 (6%) adults
• Rib fractures from severe coughing in 1 out of 25 (4%) adults

Contact your healthcare provider immediately if you or your child has any of these symptoms.