contacts including child-care center contacts, anyone directly exposed to the patient’s oral or respiratory secretions, and passengers who sat on either side of the index-patient on a ﬂight lasting /= 8 hours (MMWR 2001a; Bilukha and Rosenstein 2005). Because systemic therapy other than ceftriaxone or other third-generation cephalosporin might not eradicate N. meningitidis from the nasopharynx, patients treated for IMD with other agents such as penicillin should also receive chemoprophylaxis (Abramson and Spika 1985; Bilukha and Rosenstein 2005). Chemoprophylaxis is ideally given within 24 hours of identiﬁcation in the index patient and is of little value 14 days after disease onset (Bilukha and Rosenstein 2005). Table 1 lists currently recom- mended antibiotic prophylaxis for meningococcal disease. Fluoroquinolone-resistant N. meningitidis has been reported in Argentina, Australia, China, France, India, Spain, and most recently in the northern US (MMWR 2008). One study found azithromycin comparable in efﬁcacy to rifampin in eradicat- ing nasopharyngeal coverage of N. meningitis (Girgis 1998). When ﬂuoroquinolone-resistant meningococcal disease is identiﬁed, interim CDC recommendations are to give a single dose of 500 mg azithromycin for exposed persons 15 years old or 10 mg/kg body weight for those under 15 years old (MMWR 2008). The United States Centers for Disease Control and Pre- vention (CDC) deﬁne outbreaks as three or more conﬁrmed or probable cases of meningococcal disease in 3 months among persons residing in the same area who are not close contacts of each other with a primary disease attack rate of 10 cases/100,000 persons (Bilukha and Rosenstein 2005). In the circumstance of a conﬁrmed outbreak, public health personnel should consider vaccinating the population at risk. Mass chemoprophylaxis is not recommended except for Tetravalent meningococcal conjugate vaccine for meningococcal disease outbreaks involving populations in a limited setting such as school or for a serogroup B outbreak in those countries where a vaccine is not available (Bilukha and Rosenstein 2005). Meningococcal polysaccharide vaccines Goldschneider and colleagues demonstrated that transplacen- tal passage of antibodies to meningococci occurred resulting in passively acquired immunity to infection (Goldschneider et al 1969b). In addition they found that military recruits developed bactericidal antibodies to their own meningococ- cal isolates as a response to their carrier state (Goldschneider et al 1969b). Animal and human testing subsequently demon- strated that serogroups A and C polysaccharides stimulated immunogenicity (Gotschlich et al 1969). This led to the development of polysaccharide vaccines that were effective in preventing group C disease in US military recruits and controlling group A epidemics in Africa (Jodar et al 2002). The tetravalent polysaccharide vaccine to serogroups A, C, Y, and W-135 (MPSV4, Menomune®-A,C,Y,W-135, Sanoﬁ Pasteur, Inc., Swiftwater, Pennsylvania, US) was 85% efﬁca- cious in preventing group C meningococcal disease during an outbreak in Texas, USA (Rosenstein et al 1998). The MPSV4 vaccine is T cell-independent and the sero- group C component is poorly immunogenic in children less then 18–24 months old while the serogroup A polysaccharide does not induce an immune response comparable to adults until ages 4–5 years (MMWR 2000). In children less then 5 years, antibody levels to group A and C polysaccharides decrease signiﬁcantly within 3 years after a single vaccine dose (MMWR 2000). The vaccine also does not stimulate immune memory, and revaccination with serogroup C capsu- lar polysaccharide vaccines often results in a hypo-responsive Table 1 Chemoprophylactic agents for meningococcal disease Drug Age group Dosage and route Duration Rifampina Children 1 month 5 mg/kg orally every 12 h 2 days (Rifadin) Children 1 month 10 mg/kg orally every 12 h 2 days Adults 600 mg orally every 12 h 2 days Ciproﬂoxacinb (Cipro®) Adults 500 mg orally Single dose Ceftriaxone (Rocephin®) Children 15 years 125 mg intramuscularly Single dose Persons 15 years 250 mg intramuscularly Single dose Azithromycinc Children 15 years 10 mg/kg body weight Single dose Persons 15 years 500 mg Single dose aRifampin is not recommended for pregnant women because it is teratogenic in laboratory animals. It may decrease the effectiveness of other medications, including oral contraceptives, and alternative contraceptive methods are recommended during its use. bCiproﬂoxacin is not usually recommended for persons aged 18 years or for pregnant and lactating women because it causes cartilage damage in immature laboratory animals; however, it can be used for chemoprophylaxis of children when no acceptable alternative therapy is available. cAzithromycin is recommended as an alternative agent for chemoprophylaxis in certain areas of the US (North Dakota and Minnesota) where ﬂuoroquinolone-resistant meningococcal disease has been identiﬁed. Derived from Bilukha and Rosenstein (2005) and MMWR (2008). Therapeutics and Clinical Risk Management 2008:4(4) 741