Antibiotic Prophylaxis for Meningitis Exposure
First-Line Recommendation
For adults exposed to meningococcal meningitis, give ciprofloxacin 500 mg as a single oral dose within 24 hours of case identification. 1, 2
Who Requires Prophylaxis
Close contacts only should receive prophylaxis, defined as: 3, 1, 2
- Household members
- Child care center contacts
- Anyone directly exposed to the patient's oral secretions (e.g., kissing contacts, sharing utensils)
- Healthcare workers with unprotected direct exposure to respiratory secretions 4
The risk of meningococcal disease increases 400-800 fold in close contacts, making prophylaxis critical. 3, 2
Pathogen-Specific Approach
Meningococcal Meningitis (N. meningitidis)
Prophylaxis is mandatory and must be initiated within 24 hours. 3, 2
Adult regimens (choose one): 1, 2
- Ciprofloxacin 500 mg PO single dose (first-line due to convenience and efficacy)
- Ceftriaxone 250 mg IM single dose
- Rifampin 600 mg PO twice daily for 2 days
Pediatric regimens: 1
- Ciprofloxacin: Not recommended under 16 years
- Ceftriaxone: 125 mg IM single dose (all ages)
- Rifampin:
- Under 3 months: 5 mg/kg PO twice daily for 2 days
- 3 months to 12 years: 10 mg/kg PO twice daily for 2 days
- Over 12 years: 600 mg PO twice daily for 2 days
- Ciprofloxacin is contraindicated in pregnancy; use ceftriaxone instead
- In areas with ≥20% ciprofloxacin resistance during a 12-month period, preferentially use rifampin, ceftriaxone, or azithromycin instead
- Patients who received IV ceftriaxone for treatment do not need additional prophylaxis before discharge
Haemophilus influenzae Type B Meningitis
Prophylaxis is required ONLY when the household contains an at-risk individual: 2
- Child under 10 years of age (other than the index case)
- Immunosuppressed person of any age
If indicated, ALL household contacts AND the index case receive: 2, 6
- Rifampin 600 mg PO twice daily for 2 days (adults)
- Rifampin 10-20 mg/kg PO twice daily for 2 days (children, max 600 mg/dose)
Pneumococcal Meningitis (S. pneumoniae)
No prophylaxis is indicated for contacts. 2 Close contacts are not at increased risk and do not require antibiotics.
However, the index patient should receive pneumococcal vaccination after recovery to reduce recurrence risk (1-5%). 2
Critical Timing and Monitoring
- Prophylaxis must begin within 24 hours of case identification for maximum effectiveness. 3, 2
- Droplet precautions should continue for exposed individuals until they complete 24 hours of effective prophylaxis 1, 4
- Monitor all contacts for symptoms of meningococcal disease for at least 10 days after exposure, even after receiving prophylaxis 1, 2
- The increased risk persists for up to 6 months after exposure 2
Evidence Quality and Effectiveness
All three first-line antibiotics (ciprofloxacin, ceftriaxone, rifampin) demonstrate >95% eradication rates of N. meningitidis from the nasopharynx. 7 A Cochrane meta-analysis of 24 RCTs including 6,885 participants confirmed their effectiveness at preventing secondary cases and eradicating meningococcal carriage. 3, 7
Common Pitfalls to Avoid
- Do not delay prophylaxis waiting for culture confirmation if meningococcal disease is clinically suspected 4
- Avoid rifampin as first-line during outbreaks due to potential emergence of resistant strains 7, 5
- Do not give prophylaxis to casual contacts (e.g., school classmates, coworkers without direct oral secretion exposure) as this does not alter epidemic course 8
- Remember that penicillin-treated patients still need clearance-effective prophylaxis before discharge, but ceftriaxone-treated patients do not 3, 2