Fighting Meningococcal Disease in the "Meningitis Belt"
The CDC examines the high incidence of meningococcal disease in the “meningitis belt,” found within sub-Saharan Africa, and the efforts of the Meningitis Vaccine Project to monitor the impact of a meningococcal A conjugate vaccine.
The Centers for Disease Control and Prevention (CDC) report that rates of meningococcal disease have been on the decline in the United States; in fact, the rates are perceived to be at “historic lows.” Unfortunately, other regions of the globe are not so lucky.
One such region that holds the highest incidence of disease is what is referred to as the “meningitis belt,” which is comprised of 26 countries located within sub-Saharan Africa. Here, “major epidemics” are known to spring up every 5 to 12 years, “with attack rates reaching 1,000 cases per 100,000 population” compared with annual attack rates of 0.3 to 3 per 100,000 population in other regions of the world.
The CDC reports that, historically, serogroup A has been responsible for a staggering 90% of cases as well as large-scale epidemics that have occurred within the belt. To address this, the Bill and Melinda Gates Foundation provided funding to the World Health Organization and PATH to create the Meningitis Vaccine Project, also known as MVP, back in 2001. The project’s main underlying goal would be to eliminate serogroup A meningococcal epidemics in Africa.
By 2009, MVP researchers had developed and licensed MenAfriVac, a novel meningococcal conjugate vaccine. In December 2010, mass vaccination campaigns were launched in Burkina Faso, Mali, and Niger for individuals between the ages of 1 and 29. By December 2015, the populations of “16 of the 26 target countries” had been immunized, with “introduction of the vaccine into the routine immunization program for children ongoing.” The vaccine did what researchers set out for it to do—serogroup A meningococcal disease epidemics had been eliminated “in vaccination areas” following MenAfriVac introduction.
Serogroups C and W are now responsible for the more recent epidemics, with epidemics due to serogroup X also springing up from time to time.
According to the CDC, the risk factors for outbreaks springing up in Africa are not completely understood, but they have noted certain conditions that might be more “favorable” for epidemics. The following conditions were noted:
- Dry and dusty conditions (from December to June)
- Immunological susceptibility of the population
- Travel & large population displacements
- Crowded living conditions
The CDC also puts a specific focus on the 2017 meningococcal outbreak occurring in Liberia, which currently has 31 reported cases and 13 related deaths. Not only did CDC laboratories help classify the situation in Liberia as an outbreak, they are also working closely with global partners to support the Liberia Ministry of Health investigation.
Although the MenAfriVac has resulted in a steady decrease in the burden of disease within the belt, at least 10,000 suspected cases and several “outbreaks due to other pathogens occur each year.” In fact, in 2015, 26 districts experienced epidemics, with 20,000 individuals affected by meningitis.
When it comes to meningococcal disease, the CDC stresses that early diagnosis and treatment are imperative. The disease usually occurs within 1 to 10 days post-exposure and “presents as meningitis” in over half of cases. Common symptoms associated with meningococcal meningitis are the following: headache, fever, stiffness of neck, and sometimes, nausea, vomiting, and photophobia (discomfort/pain to eyes due to exposure to light), among others.