Organism, Causative Agent, or Etiologic Agent: Bordetella pertussis
Pertussis is a very contagious disease spread through aerosolized droplets from person to person. People with pertussis usually spread the disease by coughing or sneezing while in close contact with others, who then breathe in the pertussis bacteria.
Pertussis (whooping cough) can cause serious illness in infants, children and adults. The disease usually starts with cold-like symptoms and maybe a mild cough or fever. After 1 to 2 weeks, severe coughing can begin. Unlike the common cold, pertussis can become a series of coughing fits that continues for weeks.
In infants, the cough can be minimal or not even there. Infants may have a symptom known as "apnea." Apnea is a pause in the child’s breathing pattern. Pertussis is most dangerous for babies. More than half of infants younger than 1 year of age who get the disease must be hospitalized.
Pertussis can cause violent and rapid coughing, over and over, until the air is gone from the lungs and you are forced to inhale with a loud "whooping" sound. This extreme coughing can cause you to throw up and be very tired. The "whoop" is often not there and the infection is generally milder (less severe) in teens and adults, especially those who have been vaccinated.
Early symptoms can last for 1 to 2 weeks and usually include:
- Runny nose
- Low-grade fever (generally minimal throughout the course of the disease)
- Mild, occasional cough
- Apnea – a pause in breathing (in infants)
Because pertussis in its early stages appears to be nothing more than the common cold, it is often not suspected or diagnosed until the more severe symptoms appear. Infected people are most contagious during this time, up to about 2 weeks after the cough begins. Antibiotics may shorten the amount of time someone is contagious.
As the disease progresses, the traditional symptoms of pertussis appear and include:
- Paroxysms (fits) of many, rapid coughs followed by a high-pitched "whoop"
- Vomiting (throwing up)
- Exhaustion (very tired) after coughing fits
The coughing fits can go on for up to 10 weeks or more. In China, pertussis is known as the "100 day cough."
Although you are often exhausted after a coughing fit, you usually appear fairly well in-between. Coughing fits generally become more common and severe as the illness continues, and can occur more often at night. The illness can be milder (less severe) and the typical "whoop" absent in children, teens, and adults who have been vaccinated.
Recovery from pertussis can happen slowly. The cough becomes less severe and less common. However, coughing fits can return with other respiratory infections for many months after pertussis started.
Infants and Children
Pertussis (whooping cough) can cause serious and sometimes life-threatening complications in infants and young children, especially those who are not fully vaccinated.
In infants younger than 1 year of age who get pertussis, more than half must be hospitalized. The younger the infant, the more likely treatment in the hospital will be needed. Of those infants who are hospitalized with pertussis about:
- 1 in 5 get pneumonia (lung infection)
- 1 in 100 will have convulsions (violent, uncontrolled shaking)
- Half will have apnea (slowed or stopped breathing)
- 1 in 300 will have encephalopathy (disease of the brain)
- 1 in 100 will die
Teens and Adults
Teens and adults can also get complications from pertussis. They are usually less serious in this older age group, especially in those who have been vaccinated. Complications in teens and adults are often caused by the cough itself. For example, you may pass out or fracture a rib during violent coughing fits.
In one study, less than 5% of teens and adults with pertussis were hospitalized. Pneumonia (lung infection) was diagnosed in 2% of those patients. The most common complications in another study of adults with pertussis were:
- Weight loss (33%)
- Loss of bladder control (28%)
- Passing out (6%)
- Rib fractures from severe coughing (4%)
(Reference: Cortese MM, Bisgard KM. Pertussis. In: Wallace RB, Kohatsu N, Kast JM, ed. Maxcy-Rosenau-Last Public Health & Preventive Medicine, Fifteenth Edition. The McGraw-Hill Companies, Inc.; 2008:111-14.)
The best way to prevent pertussis (whooping cough) among infants, children, teens, and adults is to get vaccinated. Also, keep infants and other people at high risk for pertussis complications away from infected people.
In the United States, the recommended pertussis vaccine for infants and children is called DTaP. This is a combination vaccine that protects against three diseases: diphtheria, tetanus and pertussis. For maximum protection against pertussis, children need five DTaP shots. The first three shots are given at 2, 4, and 6 months of age. The fourth shot is given between 15 and 18 months of age, and a fifth shot is given before a child enters school, at 4–6 years of age. Parents can also help protect infants by keeping them away as much as possible from anyone who has cold symptoms or is coughing.
Vaccine protection for pertussis, tetanus and diphtheria fades with time. Before 2005, the only booster available contained protection against tetanus and diphtheria (called Td), and was recommended for teens and adults every 10 years. Today there are boosters for pre-teens, teens and adults that contain protection against tetanus, diphtheria and pertussis (Tdap). Pre-teens going to the doctor for their regular check-up at age 11 or 12 years should get a dose of Tdap. Teens who did not get this vaccine at the 11- or 12-year-old check-up should get vaccinated at their next visit. Adults who did not get Tdap as a pre-teen or teen should get one dose of Tdap. Pregnant women who have not been previously vaccinated with Tdap should get one dose of Tdap postpartum before leaving the hospital or birthing center. Adults 65 years and older (grandparents, child care providers, and healthcare providers) who have close contact with infants should get a dose of Tdap, following the newest vaccine recommendations. Getting vaccinated with Tdap is especially important for families with and caregivers of new infants.
The easiest thing for adults to do is to get Tdap instead of their next regular tetanus booster—that Td shot that they were supposed to get every 10 years. The dose of Tdap can be given earlier than the 10-year mark, so it is a good idea for adults to talk to a healthcare provider about what is best for their specific situation.
Children with suspected or confirmed pertussis should be kept out of school or childcare until they have completed five (5) days of antibiotic therapy. Rules for exclusion of sick children from school and childcare are outlined in the Texas Administrative Code, specifically Rule 97.7 for schools and Rule 746.3603 for childcare.
Recent Texas Trends
Over the last two decades, pertussis disease in Texas has historically occurred in waves--with peaks every 3 to 4 years followed by a subsequent sharp decline in cases. In 2009, the incidence rate of pertussis in Texas reached one of the highest levels reported in nearly 50 years at 13.5 (per 100,000 population). A large pertussis outbreak occurred in the Central Texas region from 2009 and continued into the beginning half of 2010. In 2010, the incidence of pertussis was slightly reduced to a rate of 11.2 (per 100,000 population). Upon examining incidence by age group, the highest rate of disease is found amongst infants less than 1 year of age at 128.5 (per 100,000 population). Following the typical pertussis wave pattern, the incidence decreased sharply in 2011 to 3.7 (per 100,000 population). In 2012, the cycle appears to be starting over again as there has been an increase in cases compared to 2011.
There are several important factors leading to the increased reporting of pertussis cases including waning immunity in adults and adolescents; heightened awareness of the disease among clinicians, school nurses, parents, and general public; better laboratory testing methodologies; and enhanced disease surveillance capabilities.
From 2000-2012 (as of 10/1), a total of 43 deaths were attributed to pertussis. Most of the deaths occurred in infants under 1 year of age--many in children too young to be vaccinated.
For more information on trends and statistical data, please visit the Pertussis Data page.