During 1996 the following were the most affected countries - Nigeria, Burkina Faso, Niger, Mali, Benin, Chad and the Central African Republic. Travellers are mainly at risk if they are health-care workers and have contact with patients or if they will have other close contact with the local population during their travels. The vaccine is prepared from the capsular polysaccharide of the organism. The most commonly used vaccine is the tetravalent vaccine comprising A, C, Y and W-135 serogroups, although bivalent A, C vaccines are also available. Meningococcal vaccine is a travel requirement only for pilgrims to Mecca during the annual Hajj.
Meningococcal vaccine is administered by subcutaneous injection.
Antibody production takes about 10-14 days, so travellers should be advised to be vaccinated timeously. Serogroup A vaccines are not effective in infants less than 3 months of age and are only partially effective in those 3-11 months of age. Serogroup C is not effective in children less than 2 years. Thus, children who were vaccinated at less than 4 years of age should still be considered to be at risk and, if indicated, should be revaccinated. The duration of protective immunity is not known but is at least 3 years.