The Return of Pertussis (Whooping Cough)

10/20/2010

By Katherine West, BSN, MSEd, CIC, Infection Control Consultant

Pertussis, also known as whooping cough, is caused by the bacterium Bordetella pertussis and is considered a highly communicable disease. Pertussis is known for its uncontrollable, violent coughing which often makes it hard to take in a breath.

Pertussis is an endemic (normally occurring) disease in the United States, with periodic epidemics (increase in cases) about every three to five years. In 2009, nearly 17,000 cases of pertussis were reported—and many more cases go unreported. The primary goal of pertussis outbreak control efforts is to decrease morbidity (cases of disease) and mortality (death) among infants. Pertussis most commonly affects infants and young children, and can be fatal, especially in babies less than one year of age. The secondary goal is to decrease morbidity among persons of all ages.

Transmission

Pertussis is a contagious disease found only in humans and is spread from person to person by coughing or sneezing while in close contact with others, who then inhale the bacteria. Many infants who get pertussis are infected by older siblings, parents, or caregivers who might not even know they have the disease.

The disease usually starts with cold-like symptoms and maybe a mild cough or fever. After one to two weeks, severe coughing can begin. But, unlike the common cold, pertussis can become a series of coughing attacks that continues for weeks. When someone with pertussis is able take in a deep breath a "whooping" sound emerges. This may be followed by post-tussive vomiting.

In infants, the cough can be minimal or not even there. Infants may have apnea as the main symptom. More than half of infants younger than one year of age who get the disease must be hospitalized.

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. 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%)

In teens and adults, the "whoop" is often not there, and the infection is generally milder, especially in those who have been vaccinated.

Early symptoms can last for one to two weeks and usually include

Runny nose
Low-grade fever (generally minimal throughout the course of the disease)
Mild, occasional cough

The incubation period for this disease is up to about two weeks after the cough begins. The coughing attacks may last for 10 weeks or more. In China, pertussis is known as the "100-day cough." That title seems to fit the disease.

Antibiotics serve only to shorten the amount of time someone is contagious. Recovery from pertussis can happen slowly. The cough becomes less severe and less common. However, coughing attacks can return along with other respiratory infections.

Current Outbreaks

Outbreaks of pertussis can be difficult to identify and manage. To respond appropriately (e.g., provide appropriate antibiotic prophylaxis), it is important to confirm that B. pertussis is circulating in the outbreak setting and to determine whether other pathogens are contributing to the outbreak. Polymerase chain reaction (PCR) tests vary in specificity, so obtaining culture confirmation of pertussis for at least one suspicious case is recommended any time there is suspicion of a pertussis outbreak.

Pseudo outbreaks of pertussis have resulted because of false positive test results with PCR. This underscores the importance of recognizing clinical signs and symptoms and practicing careful laboratory testing.

Institutional outbreaks of pertussis are common. Outbreaks at middle and high schools can occur as protection from childhood vaccines fades. In school outbreaks, prophylaxis is recommended for close classroom and team contacts--and the pertussis booster vaccine (Tdap), depending on age. Pertussis outbreaks in hospitals and other clinical settings can put infants and other patients at risk.

From January to October 5, 2010, more than 5,200 cases of pertussis (including nine infant deaths) were reported throughout California. This is the greatest number of cases reported in 60 years (6,613 cases were reported in 1950) and the highest incidence in 51 years (a rate of 16.1 cases/100,000 was reported in 1959). Previously, the peak was in 2005, when 3,182 cases were reported. Visit the California Department of Public Health Web site for the most recent information.
In Michigan, an increase in pertussis was first observed in the second half of 2008; it continued throughout 2009 and has continued to date throughout 2010. This is on top of a long-term rising trend in the reported number of pertussis cases since about 1990. As of August 15, 610 cases were reported for this year. In 2009 (for the complete year), 902 cases were reported. In 200, 315 were cases reported. Visit the Michigan Department of Community Health Web site for the most recent information

Prevention/Protection-Healthcare Workers

Pertussis vaccines are very effective in protecting you from disease, but no vaccine is 100 percent effective. If pertussis is circulating in the community, there is a chance that a fully vaccinated person, of any age, can contract this disease. If you have been vaccinated, the infection is usually less severe. The Centers for Disease Control and Prevention (CDC) recommend that all healthcare workers under age 65 who have direct patient care get a one-time booster of Tdap (tetanus/diphtheria/pertussis). (www.cdc.gov/vaccines) Your department should offer and pay for this vaccine.

Immunization is the best way to protect against pertussis. If you have not received a booster dose of Tdap and the patient presents with signs/symptoms of a respiratory illness, place a surgical mask on the patient. If you cannot mask the patient, place a surgical mask on yourself. Respirators are not recommended.

References

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.

Notes from the Field: Pertussis –- California, January—June 2010
MMWR June 9, 2010; 59(26):817

Use of Mass Tdap Vaccination to Control an Outbreak of Pertussis in a High School--Cook County, Illinois, September 2006-January 2007
MMWR July 25, 2008;57(29):796-9

Preventing tetanus, diphtheria, and pertussis among adults: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccines (ACIP, 2006). Recommendations of the Advisory Committee on Immunization Practices (ACIP) and Recommendation of ACIP, supported by the Healthcare Infection Control Practices Advisory Committee (HICPAC), for Use of Tdap Among Health-Care Personnel. MMWR Recomm Rep. 2006;55:1-33. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5517a1.htm Accessed June 28, 2010 /.

KATHERINE H. WEST, BSN, MSEd, CIC, has been working in the field of infection control since 1975 and actively working with Fire/EMS since 1978. She lectures nationally and internationally and has authored books, video tapes, and articles on infection control-related issues. She has served as a consultant to the Centers for Disease Control and Prevention and the National Institute of Occupational Safety & Health; she is an education specialist for the National Institutes of Health and authored theInfectious Disease Handbook for Emergency Care Personnel, now in its third edition. She is also a consultant to the U.S. Public Health Service, Federal Occupational Health, and was voted a “Hero in Infection Control & Prevention” for 2006 for her work in the field of infection control & EMS by the Association for Professionals in Infection Control & Epidemiology (APIC). Visit her Web site at www.ic-ec.com.