Meningitis epidemics in sub-Saharan Africa are ever more frequent and extending southwards. Existing vaccines are not very effective
Meningitis, an infection of the lining that covers the brain and spinal cord, has a variety of different causes, the most frequent being either viral or bacterial, one of which is meningococcus.
Five main meningococcal groups have been identified – A, B, C, W135, and Y.
In Africa, group A predominates, causing roughly 85% of observed meningococcal meningitis there.
Every year, meningitis epidemics hit Africa’s so-called “meningitis belt”, a region of 25 sub-Saharan countries that stretches from Senegal to Ethiopia with a total population of about 500 million people. And every eight to 12 years, the region is hit by a major epidemic.
Experts say this interval may be getting shorter and the meningitis belt may be extending southwards.
Groups at highest risk of infection are infants, children, and young adults. In 1996/97, the worst recent epidemic hit 250,000 people, of whom 25,000 died and 50,000 were left with some kind of disability ranging from deafness and mental retardation to paralysis or limb infection that required an amputation.
Existing vaccines have not been very effective. They protect for just three years, do not confer herd immunity, and cannot be used in children under two years old.
Social and economic impact
The disease also has a significant social and economic impact.
A study conducted in Burkina Faso during 2006/2007 found that households spent US$ 90 per meningitis case – equal to about 34% (or four months’ worth) of the average household income. When sequelae occurred, the figure went up to as much as US$ 154.
In addition, many people are afraid either to socialise or to work during a meningitis epidemic for fear of catching the disease.
Epidemics spread during the dry season from November through June, helped by overcrowded living conditions and mobile populations (pilgrimages, regional markets).
Available in the region for more than 30 years, existing vaccines have not been very effective. They protect for just three years, do not confer herd immunity, and cannot be used in children under two years old. They are used for epidemic response, not for routine immunisation.