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Whooping Cough (Pertussis) in Adults – A Complete Medical Guide

Overview

Whooping cough, medically known as pertussis, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. While it is often thought of as a childhood disease, adults can contract and transmit pertussis, sometimes experiencing atypical or milder symptoms that still pose a health risk.

Who it affects: All age groups are susceptible, but adults—especially those whose immunity has waned after childhood vaccination—are increasingly recognized as a source of community spread. In the United States, the CDC estimates around 14,000 cases of pertussis are reported annually in adults, and many more go undiagnosed.

Prevalence: Globally, the World Health Organization (WHO) records roughly 30–50 million pertussis cases each year, with a case‑fatality rate of 0.1–0.5 % in developed countries but up to 5 % in low‑income settings due to complications and delayed treatment. In adults, the disease is often under‑reported because the classic “whooping” sound is less common.

Symptoms

Adult pertussis typically evolves through three stages. The progression can last from 6 weeks to several months.

1. Catarrhal Stage (1‑2 weeks)

• Runny nose – often intermittent.
• Low‑grade fever – usually < 38 °C (100.4 °F).
• Sneezing and mild cough – resembles a common cold.

2. Paroxysmal Stage (1‑6 weeks)

• Severe coughing bouts (paroxysms) – may last 1–2 minutes, often triggered by cold air, laughing, or talking.
• “Whooping” sound – a high‑pitched gasp after a cough; present in only ~30 % of adults.
• Post‑tussive vomiting – nausea or vomiting after a coughing spell.
• Facial flushing and cyanosis – skin may turn pink or bluish due to brief lack of oxygen.
• Fatigue – due to disrupted sleep and exhaustion from coughing.

3. Convalescent Stage (2‑4 weeks or longer)

• Gradual reduction in coughing frequency.
• Persistent, mild cough may linger for months (sometimes called a “cough‑post‑pertussis syndrome”).

Because the classic “whoop” is often absent, adults may be misdiagnosed with bronchitis, asthma, or a viral upper‑respiratory infection.

Causes and Risk Factors

Cause

Pertussis is caused by the gram‑negative bacterium Bordetella pertussis. The organism releases toxins (pertussis toxin, tracheal cytotoxin, and adenylate cyclase toxin) that damage the ciliated airway epithelium, impairing mucus clearance and leading to the characteristic cough.

Risk Factors

• Waning immunity – Protection from the childhood DTaP vaccine declines after 5–10 years; booster (Tdap) is recommended every 10 years.
• Close contact with infected infants or unvaccinated children – Adults often become the source of infection for vulnerable infants.
• Smoking – Damages airway cilia, increasing susceptibility.
• Chronic lung disease (e.g., COPD, asthma) – Compromised respiratory defenses.
• Immunocompromised state – HIV, chemotherapy, or long‑term corticosteroids.
• Occupational exposure – Healthcare workers, teachers, and childcare providers have higher exposure risk.

Diagnosis

Accurate diagnosis relies on a combination of clinical suspicion, patient history, and laboratory testing.

Clinical Assessment

• Identify the characteristic cough pattern and duration (>2 weeks).
• Ask about vaccination history and recent exposure to infants or known pertussis cases.

Laboratory Tests

1. Polymerase Chain Reaction (PCR) – Detects B. pertussis DNA from nasopharyngeal swabs. Most sensitive during the catarrhal and early paroxysmal stages (first 2–3 weeks). Sensitivity ~90 % when performed correctly.
2. Culture – Gold standard but less sensitive (40‑60 %) and requires specialized media; results may take 5‑7 days.
3. Serology – Measurement of anti‑pertussis toxin IgG; useful after 2‑3 weeks of illness or when PCR is unavailable. A four‑fold rise in antibody titer between acute and convalescent samples confirms infection.

Chest X‑ray is not diagnostic but may be ordered to rule out pneumonia or other complications.

Treatment Options

Early treatment shortens the infectious period and reduces symptom severity. Antibiotics are most effective when started within the first 2‑3 weeks of cough onset.

Antibiotic Therapy

• Macrolides – First‑line agents:
  • Azithromycin 500 mg PO once daily for 5 days (or a single 1 g dose). Preferred for its short course and better tolerance.
  • Erythromycin 40–50 mg/kg/day divided every 6 hours for 14 days (more gastrointestinal side effects).
  • Clarithromycin 500 mg PO twice daily for 7 days.
• Trimethoprim‑sulfamethoxazole (TMP‑SMX) – Alternative for macrolide‑resistant strains; 160/800 mg PO twice daily for 14 days.

Antibiotics reduce contagiousness to ~5 days after initiation but have limited impact on the cough once the paroxysmal stage is established.

Supportive Care

• Hydration – helps thin secretions.
• Humidified air – eases airway irritation.
• Analgesics (acetaminophen or ibuprofen) for fever and discomfort.
• Anti‑tussive agents are generally avoided because they may suppress the cough needed to clear secretions.

Hospitalization

Reserved for adults with:

• Severe respiratory distress or hypoxia.
• Severe vomiting leading to dehydration.
• Complications such as pneumonia, rib fracture, or secondary bacterial infection.

Inpatient care may include supplemental oxygen, intravenous antibiotics, and bronchodilators.

Living with Whooping Cough (Pertussis) in Adults

Even after the acute phase, the lingering cough can interfere with daily life. Below are practical strategies to manage symptoms and prevent spread.

Daily Management Tips

• Rest and sleep – Cough episodes can be exhausting; prioritize sleep and short naps.
• Stay hydrated – Aim for 2–3 L of water daily; warm teas with honey (if not diabetic) can soothe the throat.
• Use a humidifier – Keep indoor humidity at 40‑60 % to reduce airway irritation.
• Avoid irritants – Smoke, strong fragrances, and cold, dry air can worsen coughing.
• Practice good cough etiquette – Cover mouth with a tissue or elbow; dispose of tissues promptly.
• Limit close contact – Particularly with infants < 6 months, pregnant women, and immunocompromised individuals.
• Maintain vaccination – Ensure you receive a Tdap booster every 10 years; adults caring for newborns should receive it during pregnancy (ideally between 27‑36 weeks gestation).

Work and Social Considerations

Many employers allow “sick leave” for the contagious period (usually the first 5 days after starting antibiotics). Communicate with supervisors and, if possible, work from home until coughing is well‑controlled.

Prevention

Vaccination remains the cornerstone of pertussis prevention.

Vaccination Recommendations

• Tdap (tetanus, diphtheria, pertussis) – Single dose for adults who have never received it, then a Td booster every 10 years.
• Pregnant women – Tdap during each pregnancy (27‑36 weeks) protects the newborn via trans‑placental antibodies (CDC, 2023).
• Household contacts – Everyone in close contact with an infant should be up‑to‑date on Tdap.

Other Preventive Measures

• Hand hygiene – Wash hands with soap & water for ≥20 seconds or use an alcohol‑based sanitizer.
• Avoid sharing utensils, drinks, or cigarettes with someone who has a cough.
• Stay home while symptomatic, especially during the first two weeks of cough.

Complications

While many adults recover without serious sequelae, untreated or severe pertussis can lead to complications:

• Pneumonia – The most common serious complication, occurring in up to 15 % of adult cases.
• Rib fractures – Repeated severe coughing can cause bone fractures, especially in older adults with osteoporosis.
• Urinary incontinence – Coughing spikes intra‑abdominal pressure.
• Weight loss & malnutrition – From prolonged vomiting and decreased oral intake.
• Secondary bacterial infections – Such as sinusitis or otitis media.
• Exacerbation of chronic lung disease – Asthma or COPD may flare, requiring intensified therapy.

Mortality in adults is low (< 0.1 % in high‑income countries) but rises sharply in the elderly and those with comorbidities.

When to Seek Emergency Care

References

• Centers for Disease Control and Prevention. Pertussis (Whooping Cough) – CDC. Updated 2023.
• Mayo Clinic. “Pertussis (whooping cough).” Accessed June 2024.
• World Health Organization. “Pertussis.” Fact Sheet, 2022.
• Cleveland Clinic. “Pertussis (Whooping Cough) in Adults.” 2023.
• National Institutes of Health, National Library of Medicine. “Pertussis.” MedlinePlus, 2024.

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