Pertussis ( Whooping Cough )
Symptoms and Causative Agent
Pertussis, also known as whooping cough, is an extremely contagious disease caused by the Bordetella pertussis bacterium. These bacteria produce toxins that paralyze parts of respiratory cells, leading to inflammation in the respiratory tract.
The incubation period for pertussis is generally between 7-10 days long, but can last more than a month. After symptoms first appear, the disease can take anywhere from weeks to months to fully run its course.
Initial symptoms include runny nose, sneezing, and a mild cough, which may seem like a typical cold. A mild fever also generally occurs. However, the cough slowly becomes more severe. Eventually the patient experiences bouts of rapid coughing followed by the “whooping” sound that gives the disease its common name as they try to inhale. While the coughing fit is occurring, the patient may turn blue.
While symptoms may be less severe for adults, pertussis can be extremely dangerous for infants and young children.
In between bouts of coughing, the person typically does not appear to be ill.
Although cases of pertussis have dropped dramatically in the United States since the introduction of the pertussis vaccine, the disease has caused widespread outbreaks when vaccination rates have dropped. A recent outbreak in California led to the deaths of five infants in the first six months of 2010.
Pertussis also remains a major problem in the developing world, with estimates from the World Health Organization attributing nearly 280,000 deaths to the disease worldwide in 2003.
The tendency of pertussis to be milder in adults, sometimes escaping diagnosis, further complicates disease transmission. The coughing associated with the disease may be mild enough in an adult case to be written off as a simple cold. The adult, however, will still be contagious and can easily spread the disease to infants too young to be vaccinated, or to individuals whose immunity has waned.
Treatment and Care
Treatment for pertussis is generally limited to supportive care. Antibiotics are sometimes used; however, this is primarily done to remove the Bordetella pertussis bacteria from an infected patient’s secretions, thus reducing her ability to infect others. Antibiotic treatment is unlikely to affect the course of the illness unless administered very early on.
Antibiotics may be given to individuals in contact with the patient in order to prevent infection.
Complications and Mortality Rate
Infants are particularly at risk for complications from pertussis, with the highest percentage of complications occurring in children less than six months of age. Complications include bacterial pneumonia, seizures, ear infections, and dehydration, among others; in adults, rib fracture from coughing is also possible.
The most common of these complications is bacterial pneumonia, which is also the most common cause of deaths from pertussis.
Available Vaccines and Vaccination Campaigns
Immunization against pertussis is available for children via the combination DTaP (diphtheria, tetanus, and pertussis) vaccine. The DTaP vaccination replaced the previously used DTP shot, which protected against the same three diseases but used a whole-cell preparation in the pertussis component—that is, it contained inactivated, but complete, Bordetella pertussis bacteria. For the DTaP combination vaccine, the whole-cell preparation was removed; “aP” stands for “acellular pertussis.” This vaccine provides protection against the disease by using only pieces of the pertussis bacteria, which results in fewer side effects than the whole-cell preparation.
A similar combination vaccine called Tdap offers booster protection against tetanus, diphtheria, and pertussis for adolescents and adults in certain situations.
U.S. Vaccination Recommendations
Immunization against pertussis is included on the U.S. childhood immunization schedule as part of the combined DTaP (diphtheria, tetanus, and pertussis) shot. This vaccine is given in five doses, with the first recommended at two months of age, and the last between age four and six years.
A booster dose of pertussis vaccine via the Tdap combined immunization is recommended for adults who are in close contact with children younger than one year of age. This recommendation is primarily made in order to protect children too young to be immunized, or whose immunity might not yet be strong enough to prevent pertussis infection, by reducing the number of vulnerable individuals who might develop pertussis and become contagious. Your doctor can tell you more about when to consider a Tdap booster.
Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases. Atkinson W, Wolfe S, Hamborsky J, McIntyre L, eds. 11th ed. Washington DC: Public Health Foundation, 2009. http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/pert.pdf. Accessed October 4, 2013.
Centers for Disease Control and Prevention Vaccine Information Sheet (VIS), DTaP. http://www.cdc.gov/vaccines/hcp/vis/vis-statements/dtap.html Accessed October 4, 2013.
Pertussis Vaccination: Use of Acellular Pertussis Vaccines Among Infants and Young Children Recommendations of the Advisory Committee on Immunization Practices (ACIP). (1997) Morbidity and Mortality Weekly Report, 46(RR-7);1-25. http://www.cdc.gov/mmwr/preview/mmwrhtml/00048610.htm. Accessed October 4, 2013.
Timeline Entry: 1906 Whooping Cough: Bacteria Isolated
Belgian scientists Jules Bordet (1870-1961) and Octave Gengou (1875-1957) isolated the bacterium Bordetella pertussis, the causative agent of pertussis (whooping cough), which they had first observed in 1900. It would later also come to be known as the Bordet-Gengou bacillus.See This Item In The Timeline
Timeline Entry: 1948 Whooping Cough: Vaccine Combined with Those for Tetanus and Diphtheria
The first combined DTP (diphtheria, tetanus, and pertussis) vaccines became available in the United States. This type of combined shot used a whole-cell pertussis vaccine; decades later, in the mid-1990s, the whole-cell vaccine would be replaced with an acellular version that resulted in fewer adverse reactions.See This Item In The Timeline
Timeline Entry: 1999 Whooping Cough: Acellular Vaccine Recommended
A combined dipthertia, tetanus and pertussis (whooping cough) vaccine, DTaP, that used an acellular pertussis vaccine, replaced the DTP vaccination on the U.S. Recommended Childhood Immunization Schedule. The acellular vaccine used only parts of the pertussis pathogen in order to generate immunity, and resulted in fewer side effects than the whole-cell vaccine that had been used in DTP. Eventually, the United States would cease the use of DTP completely in favor of DTaP.See This Item In The Timeline