The purpose of chemoprophylaxis is to eradicate nasopharyngeal colonization by N. meningitidis and thus prevent disease in contacts and transmission to susceptible persons(30,31,41). In addition, levels of chemotherapeutic agents in nasal secretions may prevent acquisition of the organism for a few days(31). Chemoprophylaxis is not effective in preventing disease once invasion of tissue has taken place. Internationally, there are no uniform recommendations regarding chemoprophylaxis. Most jurisdictions recommend chemoprophylaxis for household contacts, but jurisdictions vary with respect to their recommendations for other types of close contacts and for the index case(29). A recent systematic review of evidence for control policies for IMD determined that the evidence supports the use of chemoprophylaxis for household contacts and for index cases. However, there were insufficient studies to examine evidence for chemoprophylaxis in child care settings(29). Further studies are needed.
On the basis of the available evidence and expert opinion, it is recommended that cases and all close contacts (Table 3) should receive chemoprophylaxis. The index case should receive antibiotics that eradicate nasopharyngeal carriage before discharge from hospital, unless treated with an agent that also effects nasopharyngeal eradication of N. meningitidis (e.g. ceftriaxone), as therapy alone may not eliminate carriage of the organism(29,42).
Chemoprophylaxis is not routinely recommended for health care contacts, including emergency personnel. Only those health care workers who have had intensive unprotected contact (i.e. without wearing a mask) with infected patients (e.g. intubating, resuscitating or closely examining the oropharynx) require prophylaxis.
Chemoprophylaxis is unlikely to be of benefit if given > 10 days after the most recent exposure to an infectious case. Chemoprophylactic agents should be administered only to close contacts whose most recent exposure to the case was within the period of communicability (see section 7.1). Provincial and territorial public health authorities should ensure that chemoprophylaxis is available free of charge to all close contacts, as defined in Table 3. Its distribution should be facilitated through local public health authorities or, with their agreement, obtained through hospital pharmacies.
The chemoprophylactic agents recommended for the eradication of nasopharyngeal colonization by N. meningitidis are rifampin, ciprofloxacin and ceftriaxone (Table 5)(41,43). It is important to ensure that contacts requiring chemoprophylaxis complete the recommended course. Ciprofloxacin can be given in a single oral dose and is an alternative in adults, but it is contraindicated in pregnancy and is not recommended for prepubertal children. Ceftriaxone is the recommended chemoprophylactic agent for pregnant women. A case-control study among young adults in Cairo, Egypt, showed that a single dose of azithromycin (500 mg, given orally) was effective and was comparable to rifampin (600 mg twice a day for 2 days, given orally) in the short-term eradication of N. meningitidis from the nasopharynx of carriers. In addition there has been a report of the successful control of an outbreak of serogroup B meningococcal disease among pre-school children using azithromycin after failure of rifampin chemoprophylaxis(44,45). At this time, there is no specific recommendation to use azithromycin routinely for chemoprophylaxis in Canada, but further studies are warranted.
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