Meningitis is a serious infection of the thin membranes that cover the brain and spinal cord. It may be caused by a bacterial, viral or fungal infection. The most common symptoms are a stiff neck, high fever, sensitivity to light, confusion, headaches and vomiting.
Fungal meningitis mainly affects immunocompromised individuals, whereas many different types of virus may cause other forms of meningitis, which are usually benign. Several bacteria are responsible for meningitis, namely: Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae type B (Hib).
Pneumococcal meningitis is caused by the Streptococcus pneumoniae bacterium and mainly affects adults and children under two years of age. This bacterium is the most common cause of bacterial meningitis and is also responsible for other respiratory infections such as pneumonia.
Pneumococcal vaccines have significantly reduced the incidence of pneumococcal meningitis. However, the lack of evidence on the incidence of the disease and the impact of vaccine hinders decision making regarding vaccination strategies in some developing countries.
That is why AMP leads projects in collaboration with its partners to draw up data to help these countries with their vaccination strategies.
Haemophilus influenzae type B
Haemophilus influenzae type B (Hib) is a bacterium that causes meningitis and acute respiratory infections, mainly in children. In the past, lack of information on disease burden and vaccine impact hindered vaccine introduction and AMP played a key role in overcoming this limitation through vaccine impact and economic evaluations.
Currently, almost all countries globally use Hib vaccine. In this context, AMP works with countries to monitor long-term impact of Hib vaccine against meningitis, specifically to monitor whether replacement of Hib by other types of H. influenzae may occur or whether vaccine failures increase over time.
Meningococcal meningitis is a rare but serious infection caused by the Neisseria meningitidis bacterium (also known as meningococcus). In certain cases it can lead to septicaemia (a dangerous, and potentially fatal, blood infection).
The largest burden of meningococcal meningitis is an area of sub-Saharan Africa known as the “meningitis belt,” which stretches from Senegal in the west to Ethiopia in the east. At global level, it is estimated that 75,000 people die from meningococcal meningitis every year.
Prevention through mass immunization is the most effective means for reducing the burden of meningococcal disease. There are conjugate vaccines available such as MenAfriVacTM, and others against serogroups A, C, W135, and Y. With the development of broad-spectrum vaccines against serogroup B, it will be possible to drastically reduce meningococcal disease worldwide.
AMP has been fighting to reduce the number of cases of meningitis worldwide for more than 40 years. It is currently undertaking a number of studies to try and understand the impact of the vaccine on the disease and to assess the cost of meningitis surveillance so that developing countries have more evidence on the burden of the disease.