Meningitis outbreak response in sub-Saharan Africa

Overview

The meningitis belt of sub-Saharan Africa runs across the continent from Senegal to Ethiopia. This region is prone to major epidemics of meningococcal meningitis, with a high case fatality and serious sequelae that place a heavy strain on national and local health services. Until recently, most epidemics were due to Neisseria meningitidis serogroup A (NmA), such that the existing WHO guidelines have been directed mainly at the control of these epidemics. However, since 2010, countries in the meningitis belt have started to introduce a new serogroup A meningococcal conjugate vaccine (MenAfriVac) that is expected to confer both long-lasting individual protection and herd immunity. Following the successful roll-out of this vaccine, epidemics due to NmA are disappearing, but other meningococcal serogroups (e.g. NmW, NmX and NmC) still cause epidemics, albeit at a lower frequency and of a smaller size.

Due to these changes in the epidemiological pattern of meningitis, WHO set up a Guideline Development Group to review the evidence and recommendations for epidemic control in the meningitis belt. Four main topics were selected for review: operational thresholds for investigation and response to outbreaks, rapid diagnostic tests in outbreak management, antibiotic regimens in epidemics, and prophylaxis for household contacts of cases. This guideline does not include recommendations on vaccines that are already covered in existing WHO guidance.

The evidence was collected either through systematic searches for surveillance data (for questions on operational thresholds and antibiotic regimens) or through systematic literature reviews (for questions on rapid diagnostic tests and prophylaxis for households). The quality of the evidence was assessed – using Grading of Recommendations Assessment, Development and Evaluation (GRADE) – as “low” or “very low” for most questions. To move from evidence to recommendations, the framework from the “Developing and Evaluating Communication Strategies to Support Informed Decisions and Practice Based on Evidence” (DECIDE) project was followed, to assess the priority of the problem, quality of evidence, benefits and harms, values and preferences, resource use, equity, acceptability and feasibility before reaching a recommendation. Of the 16 recommendations developed (listed below), four were “strong” recommendations that were made in favour of an intervention, where potential benefits clearly outweighed any potential harms; the remaining 12 recommendations were “conditional”.