Meningococcal vaccines: past, present, and future perspectives

Meningococcal disease remains a significant global public health issue and is unique among causes of bacterial meningitis and sepsis where not only does it cause sporadic disease but also outbreaks. The prevention of meningococcal disease also presents a serious challenge . Although polysaccharide vaccines have been available for serogroup A, C, Y, and W135 for many years, serogroup C polysaccharideprotein conjugate vaccine has only recently been licensed in many countries. More recently, a conjugate vaccine for a combination of serogroup A, C, Y, and W135 has been made available. The major hurdle in achieving the goal of eradication is the development of a safe and immunogenic vaccine against serogroup B infections. Outer membrane vesicle vaccines are already used in some countries, and will likely be used more widely in the next few years, but efficacy for endemic disease in children has so far been disappointing. Through the recent availability of the meningococcal genome sequence, many new vaccine candidates are being identified and there is increasing optimism that a solution to the problem can be found. However, none of these has yet been presented as the "universal" protective antigen and work in this field continues to be held back by our limited knowledge concerning the mechanisms of natural protection against serogroup B.