The management of cases of IMD is divided into two sections, the management of sporadic cases and the management of outbreaks.
The public health response to a sporadic case of IMD includes management of the sporadic case, contact identification and tracing, and maintenance of surveillance for further cases.
When there is a strong clinical suspicion of IMD and laboratory confirmation of the diagnosis may be delayed, a specimen from a normally sterile site should be obtained for culture (or other laboratory identification of N. meningitidis) if possible and empiric therapy started quickly. The case or a proxy for the case should be interviewed to determine who are the close contacts (see Table 3). In addition to therapeutic antibiotics, the case should receive chemoprophylaxis before hospital discharge unless the infection was treated with an antibiotic that is effective in nasopharyngeal eradication of N. meningitidis(29). Nasopharyngeal cultures, used to demonstrate carriage of N. meningitidis, have no role in the identification or management of cases and contacts.
The cornerstone of prevention of secondary cases of IMD is aggressive contact tracing to identify people at increased risk of disease (i.e. close contacts). The management of close contacts of cases with conjunctivitis or pneumonia is the same as for close contacts of invasive disease. Chemoprophylaxis should be provided to close contacts in order to eliminate meningococci from any carrier within the network of close contacts, thereby reducing the risk to other susceptible individuals in the social network (see Section 10.0 Recommendations for Chemoprophylaxis)(30). Nasopharyngeal carriage of meningococci is common: at any given time about 10% of the population carry meningococci. The rationale for providing chemoprophylaxis for HCWs who are close contacts (see Table 3) is different from that for other close contacts. The time of exposure can be clearly identified. Antibiotics that eliminate carriage given soon after that exposure would be expected to eliminate carriage and prevent potential development of disease in treated individuals. Currently, no studies have assessed the effectiveness of chemoprophylaxis in this situation(31).
Close contacts of an IMD case are at increased risk of secondary disease(9-11). They should be alerted to signs and symptoms of meningococcal disease and be advised to seek medical attention immediately should they develop febrile illness or any other clinical manifestations of IMD. Chemoprophylaxis should be offered to all persons having close contact with an IMD case during the infectious period (the 7 days before onset of symptoms in the case to 24 hours after onset of effective treatment), regardless of their immunization status (see section 10.0 Recommendations for Chemoprophylaxis). Chemoprophylaxis of close contacts should be administered as soon as possible and preferably within 24 hours of case identification but is still recommended for up to 10 days (the incubation period) after the last contact with an infectious case. Chemoprophylaxis should be considered for close contacts of a case that is strongly suspected to be IMD, even if laboratory confirmation cannot be obtained within 24 hours.
The vaccination status of close contacts, including the type of meningococcal vaccine, the number of doses and age at vaccine administration, should be determined. Vaccination of susceptible close contacts, in addition to chemoprophylaxis, should be considered when the serogroup is vaccine preventable, as it may further reduce the risk of subsequent meningococcal disease; vaccination should be carried out as soon as possible (see section 11: Indications For and Use of Meningococcal Vaccines). The increased risk of disease for household contacts persists for up to 1 year after disease in the index case and beyond any protection from antibiotic chemoprophylaxis(10,11,20,21).
In the United Kingdom (UK) it is recommended that close contacts of cases with vaccine-preventable strains of N. meningitidis who received chemoprophylaxis should be offered an appropriate vaccine(32). However, in the UK a different definition of “close contacts” is used than in Canada. The National Advisory Committee on Immunization (NACI) recommends that vaccination of unimmunized household and intimate social contacts may further reduce the risk of secondary cases beyond the benefit of chemoprophylaxis(33).
While cadavers with meningococcal disease have traditionally been considered a possible source of infection risk, if the deceased person had been treated with an effective antibiotic for at least 24 hours before death, any risk is likely to be very low. If the deceased had not been treated with an effective antibiotic before death, then it is prudent for those who have occupational contact with a cadaver to follow routine infection control practices with additional droplet and contact precautions(30,34,35).
In general, when caring for the deceased, attention to routine infection prevention and control practices is sufficient, specifically, adherence to the routine infection control practices for hand washing/hand hygiene, mask/eye protection/face shields, glove and gown use. In addition, individuals who die in a home setting should be wrapped in a sheet (ideally using a plastic bag to protect the mattress and contain body fluids) and preferably kept in a cool, dry location until collected by funeral services(35).
When an IMD case has been identified in a traveller who was within the infectious period during the journey, a decision on the need for contact tracing and chemoprophylaxis should be based on the mode of transportation, the length of time fellow travellers could have been exposed to the case and the type of exposure. Any decision should be made in collaboration with the provincial or territorial epidemiologist or medical health officer.
To date, there have been no published cases of IMD resulting from transmission aboard aircraft. However, there have been reports of transmission of tuberculosis during air travel(36,37). Current surveillance systems may not detect secondary cases resulting specifically from air travel. Therefore the theoretical risk of transmission during air travel should be considered. Contact tracing of specified passengers is advised by the Centers for Disease Control and Prevention in the United States and by the Communicable Diseases Network Australia(30,36). However, prophylaxis of persons travelling in the next seat on the same plane is not advised in the United Kingdom, unless the individual is already identified as a close contact(32).
On the basis of expert opinion and the extrapolation of data on secondary transmission of tuberculosis cases aboard aircrafts, it is recommended that contact tracing be initiated if
the total time spent aboard the aircraft was at least 8 hours, including ground time on the tarmac.
It is important to note that aircraft passenger manifests are rarely kept after 48 hours, and contact tracing may be more difficult after that time.
An attempt should be made to trace, contact and offer antimicrobial chemoprophylaxis and vaccination, if appropriate, to the following:
These individuals may be at increased risk, as bacteria transmitted through respiratory droplets can be propelled short distances (< 1 m) during coughing and sneezing(35).
Outbreaks can be broadly classified as organization-based or community-based (see Table 4). Regardless of the type of outbreak, contract tracing, identification of close contacts and provision of chemo- prophylaxis to close contacts need to be conducted as described for sporadic cases (see section 7.1). There is no evidence to support the provision of widespread chemoprophylaxis for persons who are not close contacts. Widespread use may result in eradication of benign strains of Neisseria that provide protective antibodies, the generation of drug-resistant strains and an increase in the prevalence of drug-related adverse events(38).
Outbreak detection and management require complex decision-making that takes into account a variety of factors. When evidence suggests that an outbreak is occurring with increased transmission of N. meningitidis involving a vaccine-preventable serogroup in a delineated population, vaccination of persons at high risk should be considered. The type of association between cases helps to define the group at risk. Decisions regarding the use of vaccine in communities with a higher than expected rate of disease should be made in consultation with the provincial or territorial epidemiologist or medical health officer.
The following considerations can be useful in determining whether there is increased transmission of N. meningitidis within a defined population:
The criteria for vaccination should be sufficiently broad to control the outbreak. Ongoing surveillance to assess the effectiveness of outbreak control is essential and may result in changes to the target group for which vaccination is recommended.
The presence of a particular vaccine-preventable serogroup is the most important laboratory characterization in evaluating the need for immunoprophylaxis (i.e. serogroup C, W135, Y or A). The following additional factors should be taken into account when considering a vaccination campaign:
Effective local management of cases and identified outbreaks remains the cornerstone of prevention and control of IMD. Consideration of a systematic regional or provincial/territorial vaccination strategy may be needed if there are unacceptably high projected rates of disease and mortality despite ongoing regional outbreak interventions.
Outbreak management is usually carried out as an emergency measure and results in disruption of routines, a higher cost of vaccine delivery, overuse of chemoprophylaxis and the sudden demand for large quantities of vaccine. If a large proportion of the population is vaccinated because of the occurrence of multiple localized outbreaks and disease is still occurring, the decision to extend vaccination to the remainder of the population at risk may be considered.
Although general recommendations for systematic regional and provincial/territorial vaccination cannot be made, consideration may be given to this strategy in the circumstances outlined above. All levels of public health jurisdictions should ensure that they have specific contingency plans for mass vaccination. A decision of this nature must take into account public concern and political realities but cannot be based solely on these factors.
The effectiveness of outbreak control measures should be evaluated in order to ascertain whether continued occurrence of cases after a mass vaccination campaign is due to vaccine failure, poor immunization coverage, inadequate definition of the target population or other reasons.