Prospects for the prevention of meningococcal disease: special reference to group B.

Safe and effective polysaccharide (PS) vaccines for prevention of bacteraemia and meningitis due to meningococcal serogroups A, C, Y, and W135 have been licensed for a number of years in the United States and in some European countries. The bivalent AC and the tetravalent ACYW135 PS vaccines have generally been used in the civilian population only for the control of outbreaks. A major meningococcal disease problem persists in parts of Africa, especially in the so-called 'meningitis belt'. Studies by Greenwood and Wali have shown that a cost effective way to control the disease in Africa is to vaccinate the entire population of a village at the start of an outbreak. When this was done they found that further cases of group A disease ceased within ten days. There are, however, some problems with the existing PS vaccines. The group C PS is less immunogenic in young children than the three other PS, and does not protect children below 18 to 24 months of age. This problem will probably be solved by conjugation of the group C PS to a protein carrier, analogous to that which has been done with the Haemophilus influenzae type b PS.