APPENDIX A

Antimicrobial Chemoprophylaxis

Antimicrobial chemoprophylaxis of close contacts of a patient with invasive meningococcal disease is important to prevent secondary cases (Table). Close contacts include 1) household members (1), 2) child-care center contacts (2,3), and 3) anyone directly exposed to the patient's oral secretions (e.g., through kissing, mouth-to-mouth resuscitation, endotracheal intubation, or endotracheal tube management) in the 7 days before symptom onset. Health-care personnel should receive chemoprophylaxis if they were managing an airway or exposed to respiratory secretions of a patient with meningococcal disease. For travelers, antimicrobial chemoprophylaxis should be considered for any passenger who had direct contact with respiratory secretions from an index-patient or for anyone seated directly next to an index-patient on a prolonged flight (i.e., one lasting =8 hours) (4). The attack rate for household contacts exposed to patients who have sporadic meningococcal disease was estimated to be four cases/1,000 persons exposed, which is 500–800 times greater than the rate for the total population (5). In the United Kingdom, the attack rate among health-care personnel exposed to patients with meningococcal disease was 25 times higher than among the general population (6).

Chemoprophylaxis is not recommended for close contacts of patients with evidence of Neisseria meningitidis only in nonsterile sites such as an oropharyngeal swab, endotracheal secretions, or conjunctival swab. Reports of secondary cases after close contact to persons with noninvasive pneumonia or conjunctivitis are rare; there is no evidence of substantive excess risk (7–9). Furthermore, there is no indication to treat persons who are asymptomatic nasopharyngeal carriers.

Because the rate of secondary disease for close contacts is highest immediately after onset of disease in the index patient, antimicrobial chemoprophylaxis should be administered as soon as possible (ideally <24 hours after identification of the index patient). Conversely, chemoprophylaxis administered >14 days after exposure to the index patient is probably of limited or no value. Oropharyngeal or nasopharyngeal cultures are not helpful in determining the need for chemoprophylaxis and might delay institution of this preventive measure unnecessarily.

Rifampin, ciprofloxacin, and ceftriaxone are 90%–95% effective in reducing nasopharyngeal carriage of N. meningitidis and are all acceptable antimicrobial agents for chemoprophylaxis (10–13). Although sporadic resistance to rifampin and ciprofloxacin have been reported worldwide, meningococcal resistance to chemoprophylaxis antibiotics remains rare in the United States. Clinicians should report suspected chemoprophylaxis failures to their public health departments. Systemic antimicrobial therapy of meningococcal disease with agents other than ceftriaxone or other third-generation cephalosporins might not eradicate nasopharyngeal carriage of N. meningitidis reliably. If other agents have been used for treatment, the index patient should receive chemoprophylactic antibiotics for eradication of nasopharyngeal carriage before being discharged from the hospital (14).

Although azithromycin is not recommended for use as a first-line chemoprophylaxis agent, one study has reported that a single 500-mg oral dose of azithromycin was effective in eradicating nasopharyngeal carriage of N. meningitidis (15). Azithromycin, in addition to being safe and easy to administer, is also available in a suspension form and is approved for use among children. Azithromycin has been recommended for prophylaxis in the rare circumstance of sustained ciprofloxacin resistance in a local community; however, further evaluation is warranted of both the effectiveness of azithromycin in eradicating carriage of N. meningitidis and potential for development of microbial resistance (15).

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