What is the treatment and prevention for Pertussis (whooping cough)?

Treatment and Prevention of Pertussis (Whooping Cough)

For pertussis treatment, macrolide antibiotics are the first-line therapy, with azithromycin being preferred due to better adherence and fewer side effects compared to erythromycin, while prevention primarily relies on vaccination with DTaP for children and Tdap for adolescents and adults, including during each pregnancy. 1, 2

Clinical Presentation and Diagnosis

Pertussis infection progresses through three distinct stages:

1. Catarrhal stage (1-2 weeks):

   • Insidious onset with mild respiratory symptoms
   • Nasal congestion, runny nose, mild sore throat, dry cough
   • Minimal or no fever
   • Highly infectious during this period
   • Infants may present with apneic episodes and minimal cough

2. Paroxysmal stage (2-6 weeks):

   • Characteristic paroxysmal coughing fits without inspiration
   • Classic inspiratory "whoop" at the end of coughing paroxysms
   • Post-tussive vomiting
   • More frequent paroxysms at night
   • Previously vaccinated individuals may have milder symptoms without the classic whoop

3. Convalescent stage (weeks to months):

   • Gradual recovery
   • Decreasing frequency of paroxysms
   • Non-paroxysmal cough may persist for 2-6 weeks or longer
   • Viral respiratory infections may trigger recurrence of paroxysms 1

Diagnosis

• Polymerase chain reaction (PCR) testing is the preferred confirmatory test 2
• Clinical suspicion should be high when characteristic cough persists for more than 1-2 weeks

Treatment Approach

Antimicrobial Therapy

1. Primary treatment options:

   • Azithromycin (preferred): Better adherence and fewer side effects 2, 3
   • Erythromycin: Traditional treatment but with more gastrointestinal side effects
   • Clarithromycin: Alternative macrolide option

2. Erythromycin dosing (FDA-approved):

   • Adults: 500 mg every 12 hours or 250 mg four times daily
   • Children: 40-50 mg/kg/day in divided doses for 5-14 days 4

3. Timing of antibiotic therapy:

   • Most effective when administered early in the course of illness
   • Can reduce duration and severity of symptoms if given in catarrhal stage
   • Reduces period of communicability
   • Does not significantly alter the course of established disease 1, 2

Important considerations:

• Antibiotic treatment primarily aims to prevent transmission rather than improve established symptoms 2
• Approximately 80-90% of untreated patients will clear B. pertussis from the nasopharynx within 3-4 weeks 1
• Untreated and unvaccinated infants may remain culture-positive for >6 weeks 1

Prevention Strategies

Vaccination

1. Childhood vaccination (DTaP):

   • 5-dose series at ages 2,4,6,15-18 months, and 4-6 years 1
   • Primary prevention strategy for pertussis

2. Adolescent and adult vaccination (Tdap):

   • Single dose for adolescents aged 11-18 years
   • Single dose for adults aged 19-64 years
   • May replace any dose of tetanus and diphtheria toxoids (Td) vaccine 2

3. Pregnancy vaccination:

   • Tdap between 27-36 weeks' gestation with EACH pregnancy
   • Critical for protecting newborns who are at highest risk for severe disease 2, 5

4. Key vaccination considerations:

   • Immunity wanes after 5-10 years from the last pertussis vaccine dose 1
   • Neither vaccination nor natural disease confers lifelong immunity 1, 6
   • Unvaccinated or incompletely vaccinated infants <12 months have the highest risk for severe complications and death 1

Post-exposure Prophylaxis

• Recommended for:
  1. Household contacts of pertussis cases
  2. Individuals at high risk of severe illness (infants, immunocompromised persons, pregnant women in third trimester)
  3. Those in close contact with high-risk individuals 2
• Azithromycin is the preferred antibiotic for prophylaxis 2

Special Considerations

High-risk groups:

• Infants <12 months: Highest risk for severe complications and death
• Pregnant women: Vaccination protects both mother and newborn
• Immunocompromised individuals: May have more severe disease

Common complications:

• Weight loss and sleep disturbance
• Pneumothorax, epistaxis, subconjunctival hemorrhage
• Subdural hematoma, hernia, rectal prolapse, urinary incontinence, rib fracture
• Primary or secondary bacterial pneumonia and otitis media
• Neurologic complications (seizures, hypoxic encephalopathy) 1

Pitfalls to avoid:

1. Delayed diagnosis: Pertussis is often overlooked in adolescents and adults
2. Inadequate treatment: Treating only the case without prophylaxis for contacts
3. Relying on cocooning alone: Previously recommended strategy of vaccinating close contacts of high-risk individuals is no longer sufficient, as immunized individuals can still contract and transmit pertussis 2
4. Expecting antibiotics to improve established symptoms: Treatment primarily prevents transmission rather than alleviating symptoms in established disease

Remember that pertussis remains highly infectious with a secondary attack rate exceeding 80% among susceptible persons, making prompt identification, treatment, and prophylaxis essential for controlling outbreaks 1.