Pertussis

Description

• Host: humans
• Most common reservoir: adults
• Ages: all
• Distribution: worldwide
• Pattern: endemic or epidemic with outbreaks every 3 to 5 years
• Seasonality: peaks late summer–autumn; can occur year-round
• Transmission: person to person via aerosolized droplets
• Effective vaccine: available
• Immunity: neither 100% nor lifelong immunity with either infection or vaccine
• System(s) affected: respiratory
• Classic clinical manifestations include paroxysmal cough, inspiratory whoop and posttussive emesis.

Epidemiology

• Caused by Bordetella pertussis
• Typical incubation period: 7 to 10 days

Incidence

• United States (2012 most recent peak year): 48,277 cases reported
• Worldwide: 24.1 million cases and about 160,700 deaths per year

Etiology and Pathophysiology

• Toxin mediated
• Infectious process with predilection for ciliated respiratory epithelium
• Common organisms:
  • B. pertussis
  • Bordetella parapertussis

Genetics
No known genetic predisposition

Risk Factors

• Exposure to a confirmed case
• Non- or underimmunized infants and children
• Premature birth
• Chronic lung disease
• Immunodeficiency (e.g., AIDS)
• Obesity and pre-existing asthma
• Age <6 months (accounts for ~90% pediatric pertussis hospitalizations) (1)

General Prevention

• Public health measures
  • Surveillance
  • Outbreak management
  • Care of exposed individuals
• Prevention programs
• Immunizations
  • Primary childhood immunization series against pertussis followed by boosters
  • Maternal immunization during each pregnancy
  • Adults, including health care providers in close contact with infants <1 year of age, should be immunized.

Pediatric Considerations
Strategies to reduce neonatal pertussis:

• Tdap with each pregnancy, ideally between 27 and 36 weeks’ gestation
• Cocooning
• Tdap recommended for all persons in close contact with infants <1 year of age

Geriatric Considerations
Older adults are at increased risk for pertussis complications due to (2):

• Age-related changes in immunity
• Comorbid medical conditions

Commonly Associated Conditions

• Apnea in infants
• Secondary bacterial pneumonia
• Sinusitis
• Seizures
• Encephalopathy
• Urinary incontinence
• Death