Fighting disease in Africa’s meningitis belt
With more than one million cases reported since 1988 and tens of thousands of associated deaths, meningococcal meningitis is one of the most feared diseases in Africa. Meningitis—a serious infection of the thin lining that surrounds the brain and spinal cord—has many causes, usually viruses or bacteria. Viral cases typically resolve without treatment. Bacterial cases, however, can lead to death within hours. For those who survive the infection, many suffer severe disabilities such as deafness or paralysis.
Meningitis can occur anywhere but is most prevalent in Africa’s sub-Saharan meningitis belt—an area that stretches across 26 countries from Senegal in the west to Ethiopia in the east, and has an at-risk population of about 430 million. Annual meningitis epidemics can be enormous and place a massive burden on local health systems—inflicting damage long after the disease passes.
Until recently, reactive, emergency mass vaccination campaigns have been the only recourse for African countries suffering meningitis epidemics. Such campaigns, however, often occur too late to have the needed health impact and offer limited security because they use polysaccharide vaccines that elicit relatively short-lived protection and don’t promote herd immunity, among other issues. Instead of reactive campaigns, long-lasting meningococcal vaccines that can be administered to populations in advance are needed to prevent outbreaks before they start.
To turn the tables on such a deadly disease, PATH is advancing the development of vaccines that overcome these challenges and may put a stop to meningococcal meningitis once and for all.
The meningitis A solution: MenAfriVac®
In Africa, more than 80 percent of meningitis epidemics have historically been caused by Neisseria meningitidis group A, a bacterial form of the disease that mostly affects infants, children, and young adults. After a particularly devastating meningitis A epidemic in 1996-1997 sickened more than 250,000 people and killed more than 25,000, PATH, the World Health Organization, and Serum Institute of India Pvt., Ltd. (SIIPL) launched the Meningitis Vaccine Project, an initiative dedicated to developing a low-cost vaccine that would permanently end meningitis A epidemics in Africa.
That vaccine, now known as MenAfriVac®, is a meningococcal conjugate vaccine and the first vaccine to be developed specifically for Africa. In addition to its low cost (initially at $0.50 per dose), MenAfriVac® can be delivered outside of the cold chain, promotes community immunity, and provides relatively long-term protection.
Since MenAfriVac®’s first introduction in 2010, more than 235 million people have been immunized across the meningitis belt and meningitis A has virtually disappeared wherever the vaccine has been used. By 2020, the vaccine is expected to protect more than 400 million people. To ensure sustainable impact and prevent potential future epidemics, countries across the meningitis belt now need to introduce MenAfriVac® into their childhood immunization programs.
PATH continues to build the evidence base on the vaccine by conducting sustainability studies in Ghana and Mali to determine the level of protection retained over time.
A vaccine strategy to eliminate all epidemic meningitis in Africa
Africa’s meningitis story does not end with meningitis A. Other types of meningococcal meningitis can cause epidemics in Africa, including meningitis C, W, X, and Y. An epidemic caused by groups C and W in Niger, for instance, led to 8,500 cases and 573 deaths in 2015—a sobering reminder that the toolkit for preventing meningitis in Africa is not yet complete. We are again partnering with SIIPL, this time to develop an affordable conjugate vaccine against meningitis A, C, W, X, and Y, and a vaccine candidate began early-stage clinical trials in 2016.