BACKGROUND: Guidelines for the investigation and management of suspected meningococcal disease outbreaks in the United States were initially published in 1997 when outbreaks were primarily due to serogroup C Neisseria meningitidis. Since that time, quadrivalent conjugate meningococcal vaccines (MenACWY) and protein-based serogroup B meningococcal vaccines (MenB) have been licensed in the United States. In addition, the epidemiology of meningococcal outbreaks has evolved, with recent outbreaks primarily involving serogroup B at universities and serogroup C among men who have sex with men. Thus, updated guidelines are needed to assist state and local health departments to investigate and manage meningococcal disease outbreaks.
METHODS: A retrospective review of all meningococcal disease cases reported from January 1, 2009, through December 31, 2013, in the United States was performed by state health departments and CDC to identify and describe the epidemiology of meningococcal disease clusters. A meningococcal disease cluster was defined as at least two meningococcal disease cases of the same serogroup within three months. Clusters were classified as community-based if cases share no common affiliation other than a shared, geographically-defined community- or organization-based if cases are linked by a common affiliation other than a shared, geographically-defined community. A systematic review of the literature was undertaken to describe the use and impact of meningococcal vaccines and expanded chemoprophylaxis in outbreak settings from 1980 to present in all geographic areas except sub-Saharan Africa. During 2015–2016, teleconferences with an expert panel were held regularly to review current guidelines, and consider revision based on available published and unpublished data.
RESULTS: Retrospective review of meningococcal disease cases identified 251 cluster-associated cases from 62 clusters. Among these 40 were community-based, 18 were organization-based and 4 were of unknown type. Ten (56%) organization-based clusters were due to serogroup B disease, of which five were associated with universities. Based on the results of this analysis of recent U.S. clusters, systematic literature review, and expert opinion, proposed revisions to meningococcal disease outbreak guidelines were drafted and will be presented to the Advisory Committee on Immunization Practices in February 2017. Updated recommendations cover defining a meningococcal disease outbreak, threshold for considering mass vaccination campaigns, and use of expanded chemoprophylaxis.
CONCLUSIONS: Revised guidelines, taking in to account the evolving epidemiology of meningococcal disease and availability of vaccines against the most common meningococcal serogroups, have been drafted with an aim to assist state and local health departments investigate and manage meningococcal disease outbreaks.