THE INCIDENCE OF pertussis, commonly known as whooping cough, has been on the rise during the last two decades, even in countries with high vaccination coverage.1 Although it's usually thought of as a pediatric infection, pertussis is highly contagious and also infects adolescents and adults.2 In 2009, almost 17,000 cases of pertussis were reported in the United States, but many more may be undiagnosed and not reported.3
Pertussis, or "violent cough," was first described in 1540.2 The bacterium Bordetella pertussis is transmitted from person to person by large respiratory droplets during talking, coughing, and sneezing. Individuals with pertussis may be asymptomatic but still infectious. Others may develop a mild cough or paroxysmal coughing episodes. Pertussis transmission to exposed household contacts can be as high as 90%.2
Adolescents and adults may become infected and transmit pertussis to susceptible infants in the home, daycare, healthcare settings, and the community. Older adults may also transmit the infection to infants; grandparents are increasingly providing childcare for working parents, and one study found that grandparents were responsible for 6% to 8% of pertussis transmission to infants.4 Infants under age 6 months have the highest infection rate and are at greatest risk for severe disease and death.5
Pertussis on the rise
The increasing number of pertussis cases since the 1980s is due in part to waning immunity from previous pertussis infection or vaccination. Waning immunity occurs 4 to 20 years after natural infection and 4 to 12 years after vaccination.6 Additional reasons for the increase include bacterial genetic mutations, making the current pertussis vaccine less effective; a heightened awareness of the illness in certain age groups, leading to more cases being diagnosed and treated; and improved lab testing.2
Initial signs and symptoms of pertussis in adults can mimic those of other respiratory diseases such as influenza, Mycoplasma pneumoniae, and Chlamydia pneumoniae. Patients in Stage 1 of pertussis typically have coryza (runny nose), low-grade fever, and a mild cough that gradually increases in severity. This stage usually lasts 7 to 10 days. Stage 2, which usually lasts 1 to 6 weeks but can last as long as 10 weeks, is characterized by paroxysms of numerous, rapid coughs; a long inspiratory effort with a high-pitched "whoop" at the end of the paroxysms; cyanosis; vomiting; and exhaustion. During Stage 3, which lasts about 7 to 10 days, the patient begins to recover with less persistent, paroxysmal coughs that disappear in 2 to 3 weeks.7
Signs and symptoms for patients over age 65 include coughing for at least 2 weeks and up to 8 months; coughing spasms; developing a whoop; and posttussive vomiting.4,8 Patients may experience sleep disturbances, weight loss, and urinary incontinence. Complications of pertussis in adults include pneumonia, rib fractures, cough syncope, pneumothorax, aspiration, a herniated lumbar disk, inguinal hernia, subconjunctival hemorrhage, sinusitis, otitis media, hemoptysis, sepsis-like syndrome with bacteremia, intracranial bleeding, and other neurologic complications.8,9 Adults with cardiac or pulmonary disease may have a more difficult recovery from pertussis.
Testing and diagnosis
Pertussis may be underdiagnosed or not recognized in many cases due to limited lab testing, limited healthcare provider awareness of pertussis in adults, and failure to distinguish pertussis from other respiratory illnesses.8
A chest X-ray may reveal perihilar infiltrates, atelectasis, pneumonia, pneumothorax, or pneumomediastinum. Lab testing may reveal leukocytosis.
The diagnosis is confirmed by a nasopharyngeal secretion culture or polymerase chain reaction (PCR). A negative culture doesn't exclude a pertussis diagnosis because the organism is difficult to culture. The test is less likely to be positive if the culture specimen is obtained later in the course of illness, if the patient has received antibiotics or been vaccinated, or if the specimen isn't collected or handled properly.10
A PCR test is more accurate and faster than the culture. PCR findings aren't influenced by antibiotic use or vaccination. Before specimen collection, collaborate with the lab to ensure correct specimen collection and handling. Positive pertussis cases must be reported to the Department of Health.
Pertussis is treated with antibiotics. Macrolides (azithromycin, clarithromycin, and erythromycin) are preferred for the treatment or chemoprophylaxis of pertussis. Trimethoprim-sulfamethoxazole may be used as an alternative to macrolides. Treatment in adults usually lasts 7 to 14 days, depending on the antibiotic used.11 Exposed healthcare personnel and all close contacts to someone with pertussis require antibiotic prophylaxis, regardless of age or combined tetanus, diphtheria, and pertussis (Tdap) vaccination status to prevent infection and additional transmission.12,13 The CDC recommends droplet precautions until 5 days after beginning therapy.14
The CDC also recommends droplet precautions to prevent transmission of pertussis, which is spread through close respiratory or mucous membrane contact with respiratory secretions.14 Special air handling and room ventilation aren't required. Perform hand hygiene when providing care to patients with pertussis, as with all patients.
Vaccination is the best way to control pertussis and prevent its spread. A childhood pertussis vaccination program has been in place since the 1940s. Many adults are unaware that the vaccines received during childhood may not offer protection later in life. During 2005 and 2006, two new pertussis vaccines, Adacel (Tdap) and Boostrix (Tdap), became available for adolescents and adults up to age 64 as a replacement for the tetanus and diphtheria vaccine.8 The Tdap vaccine is recommended for all healthcare personnel, regardless of age.15
In 2011, the CDC issued a recommendation for Tdap vaccination in adults age 65 and older.16 This recommendation provides individual pertussis protection and prevents transmission to others. Additionally, it provides ongoing protection against tetanus and diphtheria. The vaccine is considered safe and highly effective.2 Provide patients with the Tdap Vaccine Information Statement, which provides vaccine risks and benefits, before immunization.17
Educate your patients about pertussis and discuss any concerns they have about vaccination. Common reasons for adults to decline to be vaccinated include:
- belief that healthy people don't need vaccination
- concern about adverse reactions
- belief that the vaccine causes the infection
- concern that the vaccine and administration costs aren't covered by insurance
- fear of needles
- concern about interaction with medications or a health condition.
Common adverse reactions include mild fever and erythema, edema, or tenderness at the injection site.17 Adverse reactions are a risk with any medication, including vaccines. However, declining the vaccine may result in pertussis infection with severe complications. Educate adult patients about the need for vaccination to stay healthy and help prevent pertussis outbreaks.
1. Baptista PN, Magalhães BS, Rodrigues LC. The role of adults in household outbreaks of pertussis. Int J Infect Dis
2. The Joint Commission. Tdap vaccination. Strategies from research and practice, 2011
3. Centers for Disease Control and Prevention. Pertussis (whooping cough): fast facts
4. Liang JL. Use of Tdap in adults ages 65 years and older
5. Centers for Disease Control and Prevention. Summary of notifiable diseases–United States, 2008. MMWR
6. Mertens PL, Borsboom GJ, Richardus JH. A pertussis outbreak associated with social isolation among elderly nuns in a convent. Clin Infect Dis
7. Centers for Disease Control and Prevention. Pertussis (whooping cough): clinical features
8. Cortese MM, Baughman AL, Brown K, Srivastava P. A "new age" in pertussis prevention: new opportunities through adult vaccination. Am J Prev Med
9. Spector J, Rathlev, NK. Pertussis in an elderly Asian-American man: a case report. J Emerg Med
10. Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases
. Atkinson W, Wolfe S, Hamborsky J, eds. 12th ed. Washington DC: Public Health Foundation, 2011.
11. Centers for Disease Control and Prevention. Recommended antimicrobial agents for treatment and postexposure prophylaxis of pertussis
12. Immunization Action Coalition. Ask the experts. 2010. Post exposure prophylaxis
13. Centers for Disease Control and Prevention. Guidelines for the control of pertussis outbreaks. 2006
14. Siegel JD, Rhinehart E, Jackson M, Chiarello L. The Healthcare Infection Control Practices Advisory Committee. 2007. Guideline for isolation precautions: preventing transmission of infectious agents in healthcare settings
15. Centers for Disease Control and Prevention. ACIP provisional recommendations for the use of Tdap in health care personnel. 2011
16. Recommended adult immunization schedule–United States, 2011. MMWR
17. Tetanus, diphtheria or tetanus, diphtheria, pertussis vaccine: what you need to know. Vaccine Information Statement. 2011