What prophylaxis is recommended for household contacts of an infant with bacterial meningitis?

Prophylaxis for Contacts of an Infant with Bacterial Meningitis

Household contacts of an infant with bacterial meningitis require immediate antibiotic prophylaxis within 24 hours, with the specific regimen depending on the causative organism: ciprofloxacin or rifampin for meningococcal disease, rifampin for Haemophilus influenzae type b (only if at-risk household members are present), and no prophylaxis for pneumococcal meningitis. 1, 2

Immediate Action Required

• Notify public health authorities immediately and defer all prophylaxis decisions to the Consultant in Communicable Disease Control or public health team—admitting clinicians should not initiate prophylaxis independently 3
• Prophylaxis must be administered within 24 hours of case identification for maximum effectiveness 2

Meningococcal Meningitis Prophylaxis

Who Receives Prophylaxis

• Household members, intimate kissing contacts, and anyone directly exposed to the patient's oral secretions within 7 days before illness onset 3, 1
• Close contacts are defined as those living or sleeping in the same household, pupils in the same dormitory, boyfriends/girlfriends, and university students sharing a kitchen 3
• Classmates and nursery contacts do NOT require prophylaxis unless they meet close contact criteria 3

First-Line Antibiotic Regimen: Ciprofloxacin (Preferred)

• Adults and children >16 years: 500 mg oral single dose 3, 1, 2
• Children 5-12 years: 250 mg oral single dose 3
• Children <5 years: 30 mg/kg (maximum 125 mg) oral single dose 3
• Ciprofloxacin is preferred because it is a single dose, readily available, and safe in pregnancy 3

Alternative Regimen: Rifampin

• Adults and children >12 years: 600 mg orally twice daily for 2 days 3, 1
• Children 1-12 years: 10 mg/kg orally twice daily for 2 days 3, 1
• Infants <12 months: 5 mg/kg orally twice daily for 2 days 3, 1

Alternative Regimen: Ceftriaxone

• Adults: 250 mg IM single dose 1, 2
• Children: 125 mg IM single dose 1

Critical Considerations

• The risk of meningococcal disease increases 400-800 fold in close contacts, with secondary attack rates of 2-4 per 1000 population 2
• An increased risk persists for 6 months after exposure, even with prophylaxis—general practice records should be flagged 3, 2
• Contacts should be monitored for symptoms for at least 10 days after exposure 1, 2
• Droplet precautions should continue until contacts have received 24 hours of effective prophylaxis 1, 2

Vaccination

• Offer meningococcal C vaccine to unvaccinated contacts of non-B serogroup cases 3
• If 2 or more cases of serogroup B disease occur in the same family, offer serogroup B vaccination to all household contacts 3

Haemophilus influenzae Type B Prophylaxis

Who Receives Prophylaxis

• Prophylaxis is required ONLY when the household contains an at-risk individual: a child under 10 years (other than the index case) or an immunosuppressed person of any age 2, 4
• If no at-risk household member exists, prophylaxis is NOT indicated 2
• All household contacts AND the index case should receive rifampin if an at-risk individual is present 2

Rifampin Regimen

• Adults: 600 mg orally once daily for 4 days 2
• Children 1 month-12 years: 20 mg/kg (maximum 600 mg) orally once daily for 4 days 2
• Infants <1 month: 10 mg/kg orally once daily for 4 days 2

Day-Care Center Contacts

• The decision to provide prophylaxis to day-care contacts is controversial because the risk of secondary infections is uncertain 4
• Consider prophylaxis only if multiple cases occur or if there are children under 2 years attending 5

Pneumococcal Meningitis

Close contacts of pneumococcal meningitis do NOT require antibiotic prophylaxis, as they are not at increased risk 2, 6

Index Case Management

• The index case should receive pneumococcal vaccination after recovery to reduce recurrence risk (approximately 1-5%) 2, 7

Common Pitfalls to Avoid

• Do not delay prophylaxis waiting for laboratory confirmation—initiate based on clinical suspicion 2
• Do not prescribe prophylaxis to school or nursery contacts of meningococcal cases unless they meet close contact criteria—this leads to overuse and antibiotic resistance 3, 8
• Do not assume the index case received adequate prophylaxis from treatment antibiotics—only IV ceftriaxone provides adequate nasopharyngeal eradication; patients treated with penicillin or other agents require additional prophylaxis before discharge 2
• Remember that prophylaxis only eradicates nasopharyngeal carriage; it cannot treat individuals already incubating the disease 4