Neisseria meningitidis serogroup A vaccines: an overview

A recent report by the Weekly Epidemiological Record of an outbreak of Neisseria meningitidis serogroup A in the Great Lakes region shows that meningococcal epidemics are an unsolved problem in resource-poor countries, particularly in Africa [1]. During the last epidemic wave in the 1990s, about 350,000 people developed meningitis and 1000 people died [101]. An effective polysaccharide vaccine has been available since the early 1970s. Unfortunately, attempts to contain the epidemics by timely detection of cases through active surveillance and prompt mass vaccination campaigns have failed to prevent the deaths of thousands of people in several African countries in the 1980s and 1990s. This article describes the epidemiology of N. meningitidis serogroup A, the available polysaccharide vaccines, their advantages and limitations. The current vaccination policies and their economic implications are discussed, to clarify why the use of an effective vaccine has, to date, been disappointing. The recent exciting developments with respect to conjugate vaccines are described.