• Chemoprophylaxis should be given to those individuals who came into "close contact" with someone infected with meningitis due to meningococcal infection (i.e. Neisseria meningitidis).  It should be given as early as possible following the exposure; when there is a high index of suspicion, do not wait for culture results to give prophylaxis.
• Chemoprophylaxis is generally not indicated when the etiology is Streptococcus pneumoniae, and should be reserved for young children who have not received a Haemophilus influenzae type b (Hib) vaccination and immunocompromised close contacts when the etiology is Hib.
• While the definition of a "close contact" remains somewhat ambiguous, it generally refers to individuals who have had prolonged (>8 hours) contact while in close proximity (<3 ft) to the patient, or who have been directly exposed to the patient's oral secretions between one week prior to the onset of the patient's symptoms until 24 hours after initiation of appropriate antibiotic therapy.
• Standard regimens for antimicrobial prophylaxis include ciprofloxicin, ceftriaxone, and rifampin.  Adults typically require a single oral dose of 500 mg of ciprofloxicin or 250 mg of intramuscular (IM) ceftriaxone, while individuals under age 15 may receive a single dose of 150 mg of IM ceftriaxone.

References

• Bilukha, OO, Rosenstein, N. Prevention and control of meningococcal disease: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 2005; 54(RR-7):1.
• Gardner P. Clinical practice. Prevention of meningococcal disease. N Engl J Med 2006; 355:1466.
• Schwartz B, Al-Tobaigi A, Al-Ruwais A, et al. Comparative efficacy of ceftriaxone and rifampin in eradicating pharyngeal carriage of group A Neisseria meningitidis. Lancet 1988; 1:1239.