Pertussis: an overview of the disease, immunization, and trends for nurses.
Overview of Pertussis
Pertussis is primarily considered an illness of childhood characterized by coughing, particularly whooping cough, and post-tussive emesis. The result of the cough is being out of breath with a noisy inspiratory stridor, called whooping, caused by laryngeal spasm; hence, the common name of whooping cough (Lippincott Williams & Wilkins, 2006). The word pertussis is derived from the Latin word per, meaning thoroughly, and the word tussis, meaning cough (Merriam-Webster, Inc., 2004). Pertussis is caused by Bordetella pertussis, a gram-negative coccobacillus, which causes an inflammation of the larynx, trachea, and bronchi, and is characterized by recurrent bouts of spasmodic coughing continuing until breath is exhausted (Lippincott Williams & Wilkins, 2006).
Course of Illness: Stages of Pertussis
Pertussis is a disease characterized by classic symptoms of severe coughing, whooping, and post-tussive vomiting, which can last for many weeks. The incubation period for pertussis is most commonly 7 to 10 days, with a range of 4 to 21 days. The disease period is divided into three stages. The first stage, catarrhal, is characterized by upper respiratory symptoms of runny nose, sneezing, and a mild cough, and can be easily dismissed as symptoms resembling the common cold. In the next stage, paroxysmal, the cough worsens to bouts of spasmodic coughing or whooping cough. Of note, the characteristic whooping cough may not be evident in infants under six months of age, who more commonly have symptoms of cyanosis and post-tussive emesis. The second stage, paroxysmal, can last up to 10 weeks, with a typical duration of one to six weeks. A low-grade fever may or may not be present in the catarrhal and paroxysmal stages. In the final stage, convalescent, the cough gradually improves over a two to three-week period (Centers for Disease Control and Prevention [CDC], 2007).
Transmission of pertussis occurs through direct contact with respiratory droplets from mucous membranes of those infected with pertussis (CDC, 2010c). Pertussis spreads quickly from person to person through coughing and sneezing. Transmission can occur from contact with recently contaminated items from an infected person (CDC, 2007). The communicability of pertussis is high, with an estimated 90% attack rate in household contacts developing the disease after exposure (CDC, 2010c).
Epidemiology and Trends In Pertussis
Information for the rates of immunization in the U.S. is available through the National Immunization Survey (NIS) (CDC, 2010d). (For more information, see http://www.cdc.gov/nis). According to the NIS (July 2008 to June 2009), 84.9% of children had received four doses of diphtheria, tetanus toxoid, and acellular pertussis (DTaP) by 35 months of age in the U.S. When stratified by race, the national rates for the same time period for White children were 85.6%, Black children 81.1%, and Hispanic children 85.0%. Three doses of DTaP are recommended by 6 months of age; therefore, by 7 months of age, the expected three doses should be complete, but the reported rate was only 70.3% for the U.S. in 2009. These data show a delay in acquiring immunizations for children and a disparity among races (CDC, 2010d).
The NIS also provides data for adolescents and adults. For adolescents 13 to 17 years of age, 40.8% had received one or more doses of tetanus toxoid, reduced diphtheroid, and acellular pertussis (Tdap), with 76.2% receiving 1 or more doses of tetanus and diphtheria (Td) or Tdap in 2009. In the summer of 2007, adults reported a vaccination rate of 2.1% with Tdap in the previous two years. Adults had received the tetanus vaccine at a rate of 57.2%, with 20.7% receiving Tdap as tetanus vaccine. Data for adolescents and adults indicate these groups are vulnerable to pertussis due to decreased immunization rates (CDC, 2010d).
Incidence of pertussis has increased steadily since the 1980s (CDC, 2010c). In 2008, more than 13,000 cases of pertussis were reported, with the CDC (2010c) citing a disproportionate number of cases in adolescents and adults. Pertussis can cause serious illness in infants, and death can occur if left untreated (CDC, 2005, 2010c). Available data on the immunization rates and disease of pertussis in the U.S. indicate a need for continued diligence in interventions for pertussis prevention. Nurses have a key role in prevention of the disease.
Diagnosis of Pertussis
The diagnosis for pertussis can be made through a history of symptoms and a variety of laboratory tests, including culture, polymerase chain reaction (PCR), direct fluorescent antibody (DFA), and serology (CDC, 2007). However, the diagnosis of pertussis is often made on the basis of clinical symptoms, particularly a cough lasting greater than two weeks with paroxysmal characteristics and post-tussive emesis (CDC, 2007).
Culture is considered the gold standard laboratory test for pertussis (CDC, 2007; World Health Organization [WHO], 2005). The culture is highly specific to the Bordatella pertussis organism (see Table 1). The culture requires specimens that contain nasopharyngeal secretions obtained by aspirate or swab (CDC, 2008). The cultures rely heavily on the type of culture obtained; a culture obtained by nasal aspirate isolates more secretions than nasal swab (Tilleya et al., 2000). In addition, culture results are most reliable if obtained within the first two weeks of cough onset. Results may take up to two weeks for a final report (CDC, 2008).
Other tests, such as the PCR, DFA, and serology tests, can also be used in diagnosis of pertussis (see Table 1). These tests also require specimens that contain nasopharyngeal secretions obtained by aspirate or swab (Tilleya et al., 2000). The PCR, with its increased specificity and capability for expedited results, is the preferred diagnostic test for pertussis. Unfortunately, the PCR has a poor sensitivity and is highly affected by specimen collection techniques similar to culture (Tilleya et al., 2000). DFA testing can be used as a rapid screening tool but has a low specificity for pertussis. Both the PCR and DFA have high false-positive rates. In the later stages of illness, serologic tests can be used to detect pertussis antibodies, requiring a substantial change in titers for pertussis antigens; results are typically available too late in the course of the illness to be clinically useful (CDC, 2008). The serology test, however, does not distinguish between exposure to disease and exposure to vaccine if the individual has been immunized within the last year, limiting usefulness of this test in recently vaccinated individuals (CDC, 2007; WHO, 2005).
The CDC (2007) recommends the use of PCR in addition to culture in the diagnosis of pertussis. In the clinical setting, the nurse will frequently obtain the culture and PCR. With the long delay for culture results, treatment will often be initiated presumptively based on symptoms at the time culture is obtained. This may help minimize potential spread of the disease.
Treatment of Pertussis
The disease is most contagious in the catarrhal stage. Without treatment, individuals may be contagious for up to three weeks after the initial onset of cough. Erythromycin, a macrolide, is the treatment approved by the CDC for pertussis. Other alternative treatments are azithromycin and trimethoprim-sulfamethoxazole (see Table 2). Antibiotics given during the incubation period or early catarrhal stage may improve the course and prevent spread of the disease. During the late catarrhal stage, antibiotic therapy will not change the course of the disease but may reduce transmission of the disease to others (WHO, 2005). It is important to diagnosis pertussis in the early stages because antibiotic therapy in the later stages will not alter the course of the disease, which can prolong the course of the illness and lead to potential death, especially in infancy.
Prevention of Pertussis: Issues and Trends
The pertussis vaccine is the most effective means for disease prevention (Khan et al., 2006). Thus, the primary risk factor for pertussis is being unprotected or inadequately protected from immunizations. Another risk factor is age. Pertussis is most common in adolescents 11 to 18 years of age whose vaccine immunity has waned, and infants under 6 months of age who are inadequately protected by current immunization schedules (AAP, 2006). Other issues in the prevention of pertussis through immunizations are barriers to access and parental decision not to immunize children.
Adolescents become susceptible to pertussis when vaccination immunity wanes (CDC, 2010c). This waning immunity also occurs in adults. Lifelong immunity to pertussis does not exist. Adolescent age groups (11 to 18 years) and adults 19 to 64 years of age have likely benefitted from the pertussis vaccine booster added to immunization schedules in 2006 (AAP, 2006). Adolescents and adults not immunized are a common source of infection for unprotected infants (CDC, 2007).
Infants are another age group of focus in the prevention of pertussis. They are often either not protected by immunization prior to 8 weeks of age or are inadequately protected by immunization at less than 6 months of age. With increased susceptibility to the disease, infants can be infected through direct contact with respiratory droplets from family and caregivers from a cough or shared toy. Mothers have been identified as a source of pertussis infection for infants. This has prompted new recommendations from the CDC (2008) to have postpartum women receive the vaccine in the immediate postpartum period before discharge from hospital or birthing center. With infants being at greatest risk for severe illness and death (CDC, 2005, 2008), prevention of pertussis in infants is a primary concern.
Lack of access to preventive care is a common barrier to receiving recommended immunizations. Lack of access results in delay of immunizations or non-adherence to current immunization recommendations. In a study from Hawaii census data, risk factors for delayed immunizations included delayed immunization at 3 months of age, living in an area where adults had a low proportion of postsecondary educations, and living in an area where high proportions of adults spoke a language other than English (Whitehead, Cui, De, Ayers, & Effler, 2007). The effects of health insurance status and barriers to health care were not evaluated in the Hawaii census tract study because data were obtained from school health records. This study is valuable in describing risk factors for delayed immunizations in children attending school, but more studies such as this are needed to describe barriers to immunization access.
Parents may decide not to immunize their children due to personal or religious beliefs. Children entering school in the U.S. are required to provide documentation of immunizations (Omer et al., 2006). However, non-medical exemptions (including religious or personal reasons) are offered by most states. In a study by Omer et al. (2006), the availability of personal belief exemptions and the ease of obtaining personal exemptions by parents were associated with increased pertussis incidence. Parents are often concerned about the perceived risks of vaccines, such as side effects or illness, and may request personal exemptions. Children with immunization exemptions are considered to be at an increased risk of pertussis disease and increase the disease transmission in the community.
The impact of vaccine decisions demonstrated that health care workers, including nurses, can have inaccurate perceptions about pertussis and the pertussis vaccine (Goins, Schaffner, Edwards, & Talbot, 2007). Health care workers were found to be inadequately vaccinated and verbalized the lack of intention to receive the pertussis vaccine, despite provisional CDC recommendations for pertussis vaccination for health care workers at time of study. In addition, nurses and health care workers with children present in the home were less likely to intend to receive the vaccination (Goins et al., 2007). The study further demonstrated that health care providers affected the efficacy of a hospital vaccine program for pertussis, with nurses' personal beliefs and practices about vaccines inferred. This is an area of concern because health care workers who have not been vaccinated can be a source of pertussis infection and outbreaks in obstetric and neonatal settings (CDC, 2008).
In summary, pertussis can be prevented through immunizations. Individuals need appropriate immunization to reduce pertussis risk. Barriers to health care access, personal decisions regarding health care, and knowledge deficits contribute to the lack of immunizations administered, and thus, the prevention of pertussis. Knowing the barriers to immunizations allows nurses to tailor interventions to at-risk groups.
Prevention of Pertussis: Implications for Nursing
Nurses have a role in the prevention of pertussis through immunization programs and education, and administration of the vaccine. The recognition of pertussis and reporting to the appropriate providers and agencies is another intervention to aid in the control of pertussis outbreaks in the community.
Immunization Programs For Pertussis
The nurse has an important role in vaccine programs and should be aware of the available vaccines and their method of administration. In the U.S., several types of effective vaccine are available. Current vaccines are the diphtheria, tetanus toxoid, and acellular pertussis (DTaP) in early childhood, and the tetanus toxoid, reduced diphtheroid, and acellular pertussis (Tdap) for adolescents and adults (CDC, 2010a) (see Table 3). There are two available Tdap vaccines: Boostrix[R] (GlaxoSmithKline: Biologicals: Rixensart, Belgium) and Adacel[R] (Sanofi Pasteur, Swiftwater, PA) (AAP, 2006).
The combination DTwP has more widespread use internationally (WHO, 2005). The whole-cell vaccine is used in many countries outside the U.S. because the vaccine is more cost-effective and has similar safety and efficacy as the acellular vaccine (CDC, 2007). In the U.S., the acellular vaccine is the preferred type of vaccine for the complete series since 1996 (CDC, 2007; Khan et al., 2006) because it has a better side effect profile.
For both the DTaP and DTwP vaccines, combination vaccines are available that include inactivated polio virus (IPV), Haemophilus influenza B (Hib), and hepatitis B (Hep B) (WHO, 2005). The vaccine is administered intramuscularly in the thigh of infants or upper arm in older children, adolescents, and adults.
The current childhood immunization schedules (CDC, 2010a) in the U.S. recommends a series of DTaP in infancy and early childhood (see Table 4). In addition, a Tdap is recommended for adolescents 11 to 18 years of age, adults, postpartum women, close contacts of infants less than 12 months of age, and all health care personnel with direct patient contact if they have not previously received Tdap (AAP, 2006; CDC, 2010a, b). In adults, the current recommended tetanus toxoid injection every 5 to 10 years should be replaced once with a Tdap (CDC, 2010b). This dose of Tdap can be administered as soon as two years from the last Td, and shorter intervals than two years can be used in practice (CDC, 2010b).
Reporting of Pertussis Cases
The nurse has an important role in reporting cases to the appropriate authorities to minimize a potential outbreak in the population. In the U.S., pertussis is a notifiable disease at the state level. All health care providers, including nurses, are required by law to report any laboratory-confirmed or clinically diagnosed cases of pertussis. The reporting ensures public health follow up, identification of outbreaks, and monitoring of disease trends (Georgia Department of Human Resources, n.d.). For information specific to your state, visit your state's Department of Human Resources Web site.
The CDC (2007) receives information from all states on pertussis outbreaks. This information includes pertussis case information via the National Electronic Transmittal System for Surveillance. Another system, the Supplementary Pertussis Surveillance System, receives disease information as well. The surveillance systems for pertussis in the U.S. are helpful in monitoring disease trends and have noted the increased incidence of pertussis in all age groups, particularly adolescents and adults (CDC, 2007).
In recent years, a closer analysis of these outbreaks has prompted revisions to the immunization schedule in the U.S. Khan et al. (2006) provides an example of an outbreak of pertussis in Missouri of primarily adolescents in school. The study concluded that missed doses of vaccine, early administration of fifth close of vaccine, and a short interval between fourth and fifth vaccine doses increased the risk of pertussis. This study gave evidence to the importance of completion of the vaccination series and the prevalence of adolescents in pertussis outbreaks.
For nurses, the primary intervention for pertussis is education about immunizations and administration of the pertussis vaccine. Another intervention is the prompt evaluation and treatment of potential cases, with the nurse in a pivotal role of recognizing cases and notifying the appropriate authorities and other health care providers. Nurses also have an important role in minimizing barriers to immunizations through active involvement in reminding parents about immunization schedules, avoiding missed opportunities to vaccinate in the clinical setting, and participating in non-traditional places for immunizations, such as shopping malls, grocery stores, and schools.
Pertussis remains a concern in the U.S. despite the availability of an effective vaccine. Pertussis outbreaks have occurred in the community due to the highly communicable nature of the disease and a waning immunity in the population. In response to the resurgence, new vaccination guidelines recommend a booster immunization for adolescents and adults in the U.S. Results of these changes to the immunization schedule may not be fully evident for years to come. For now, pertussis warrants a watchful eye by nurses who have an important role in the prevention of a current health concern.
Statement of Disclosure: The authors reported no actual or potential conflict of interest in relation to this continuing nursing education article.
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Regena Spratling, MS, RN, CPNP, is a Doctoral Student, Georgia State University, Atlanta, GA, and an Assistant Professor, North Georgia College and State University, Dahlonega, GA.
Myra Carmon, EdD, RN, CPNP, is an Associate Professor, Georgia State University, Dahlonega, GA
Table 1. Diagnosis of Pertussis Test Specificity Sensitivity Nursing Implications Culture 100% 36% Highly specific Aspirate specimen best Collect within 2 weeks of symptom onset Results (1 to 2 weeks) Polymerase 98% to 99% 89% to 95% Highly specific and Chain sensitive Reaction Aspirate specimen best (PCR) Collect along with culture Results (within 3 days) High false-positive rates Direct 94% to 98% 5% to 11% Less specific and Florescent sensitive than culture Antibody and PCR (DFA) Rapid results (within hours) High false-positive rates Serology N/A N/A Not routinely used for diagnosis in clinical setting Sources: CDC, 2008; Tilleya et al., 2000. Table 2. Pharmacologic Treatment of Pertussis Medication Duration Dosage Erythromycin 14 days Infants and children: 40 to 50 mg/kg/day divided every 6 hours Azithromycin 5 to 7 days Infants and children: 10 mg/kg/ dose once daily Trimethoprim- 14 days Infants and Sulfamethoxazole children: 8 mg/kg/ day of trimethoprim and 40 mg/kg/day of sulfamethoxazole divided into twice daily doses Medication Treatment Information Erythromycin Not recommended for infants less than 1 month old Azithromycin Can be used in infants less than 6 months old and those intolerant of erythromycin Trimethoprim- Not recommended for Sulfamethoxazole infants less than 2 months old Sources: CDC, 2005; Taketomo, Hodding, & Kraus, 2007. Table 3. Vaccines for Pertussis Vaccine Age Group Vaccine Information DTaP Infants and Local reactions: children Pain, redness, swelling Mild systemic reactions: Drowsiness, fretfulness, low-grade fever Systemic reactions: Fever (105[degrees]F or higher), febrile seizures, persistent crying lasting 3 hours or longer, hypotoniG hyporesponsive episodes have been reported in fewer than 1 in 10,000 doses Tdap Adolescents and Local reactions: Boostrix[R] adults Pain, redness, Adacel[R] Age 10 to 18 years swelling at the Age 11 to 64 years injection site Systemic reactions: Low-grade fever, headache, fatigue and gastrointestinal symptoms DTwP Infants and Used internationally children More adverse reactions than DTaP Note: The single contraindication to the vaccine is previous anaphylactic reaction to the vaccine. Sources: CDC, 2010a; Khan et al., 2006. Table 4. Immunization Schedule for Pertussis Dose Vaccine Number Age DTaP 1 2 months 2 4 months 3 6 months 4 15 to 18 months May be received as early as 12 months if 6 months since third dose 5 4 to 6 years Frequently given at 4 years of age as 5 doses required for school entry Tdap Booster 11 to 18 years Adults Postpartum women Sources: AAP, 2006; CDC, 2010a.
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|Author:||Spratling, Regena; Carmon, Myra|
|Article Type:||Disease/Disorder overview|
|Date:||Sep 1, 2010|
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