Existing vaccines cannot prevent epidemics
Vaccines against different forms of meningococcal disease have been available for over 30 years. Since they only protect those vaccinated for a maximum of 2-3 years and do not protect young children, who are particularly vulnerable to the disease, they are unable to prevent epidemics. As a result, mass vaccination campaigns have to be repeated year after year. Although the ability to develop a safe and effective vaccine, through what's called "conjugation" technology, for Africa had existed for 10 years, by 1999 all programmes to develop vaccines for A or A/C had ceased.