What to do after possible exposure to pertussis (whooping cough)?

Management After Possible Exposure to Pertussis (Whooping Cough)

After possible exposure to pertussis, postexposure prophylaxis with azithromycin should be administered, especially for household contacts and those in high-risk settings, regardless of age or vaccination status. 1

Identifying Exposure Risk

• Consider postexposure prophylaxis if you've had:
  • Direct contact with respiratory secretions of an infected person
  • Close, prolonged contact with someone diagnosed with pertussis
  • Household exposure to a pertussis case
  • Exposure in settings with high-risk individuals (infants, pregnant women, immunocompromised persons)

Recommended Prophylactic Treatment

First-line treatment: Azithromycin

• Adults: 500 mg on day 1, followed by 250 mg once daily on days 2-5 1
• Children: 10 mg/kg (maximum: 500 mg) on day 1, followed by 5 mg/kg per day (maximum: 250 mg) on days 2-5 1

Alternative options (if macrolide intolerance):

• Clarithromycin: 500 mg twice daily for 7 days (adults) or 15-20 mg/kg/day in two divided doses for children 2
• Trimethoprim-sulfamethoxazole: One double-strength tablet twice daily for 14 days (adults) or 8 mg/kg/day TMP, 40 mg/kg/day SXT in 2 divided doses for children 2

Work and School Exclusion Guidelines

• If you remain asymptomatic while receiving chemoprophylaxis after exposure, you do not need to be excluded from work or school 2
• If you cannot receive chemoprophylaxis and work with high-risk individuals (especially children <4 years), exclusion may be required from 7 days after first exposure until 14 days after last exposure 2

Monitoring for Symptoms

Monitor for pertussis symptoms for 21 days after exposure:

• Initial cold-like symptoms (catarrhal stage): runny nose, mild cough, low-grade fever
• Progression to paroxysmal coughing fits, often with a "whoop" sound
• Post-tussive vomiting
• Prolonged cough lasting weeks to months

When to Seek Medical Care

Seek immediate medical attention if you develop:

• Persistent cough lasting >7 days without another apparent cause
• Paroxysmal coughing episodes
• Post-tussive vomiting
• Inspiratory "whooping" sound

Diagnostic Testing if Symptoms Develop

If symptoms develop, diagnostic testing should include:

• Nasopharyngeal aspirate or swab for culture and/or PCR testing 2
• Testing should be performed early in the course of illness for best results

Important Considerations

• Pertussis is highly contagious with secondary attack rates exceeding 80% among susceptible persons 1
• Early prophylaxis is crucial as it can prevent or reduce severity of disease if started promptly
• Immunity from vaccination wanes after 5-10 years, so even vaccinated individuals can contract pertussis 1
• Treatment is most effective when initiated during the catarrhal stage (first 1-2 weeks) 1

By following these guidelines promptly after exposure, you can significantly reduce the risk of developing pertussis and prevent further transmission to vulnerable populations.