Meningococcal disease is a potentially fatal illness caused due to bacterium known as Neisseria meningitides. The bacteria is known to cause serious infection in the meninges, which are thin layers of connective tissues surrounding the brain and spinal cord. Common clinical symptoms of meningococcal disease are meningitis, bacteremia, and pneumonia. Other less common indications include myocarditis, endocarditis or pericarditis, arthritis, conjunctivitis, urethritis, pharyngitis, and cervicitis. Symptoms associated with these disease include high fever, neck stiffness, confusion, nausea, vomiting, lethargy, and petechial rashes.
Meningococcal vaccines are known to be found on the World Health Organization’s List of Essential Medicines. The bacteria can be classified into over 10 serotypes based in their immunologic reactivity. Currently, globally marketed meningococcal vaccines are of four types - polysaccharide-based, bivalent (Serogroup A and C), trivalent (Serogroup A, C and W-135), and tetravalent (Serogroup A, C, Y and W-135). There is currently only one vaccine available for Serogroup B in the US, while it account for over one-third of the disease cases in the country. The nature and components of the vaccines are purified, heat-stable, lyophilized capsular polysaccharides derived from the meningococci of the respective serogroups.
Disease epidemiology of the meningococcal disease has undergone a radical change over the last century. Case-fatality ratios have witnessed a decline of from a high of 70% in the first part of the twentieth century to less than 15% after 2000. Of late the disease caused by Serogroup Y has increased from prevalence rate of 2% to over 35% between 1990 and 2005. The disease is contractible in nature primarily through antimicrobial chemoprophylaxis. There are currently three meningococcal vaccines available in the US to prevent this...