A half-century of meningococcal vaccines.

The first safe and effective vaccine for the prevention of invasive meningococcal disease was created fifty years ago. The vaccine employed a novel platform, polysaccharide capsular antigen, based on the discovery that anticapsular antibody conferred protective immunity in humans. As with most new paradigms in vaccinology, it derived from important basic research from other scientific disciplines over the preceding years. The success of the first monovalent polysaccharide vaccine in nearly eliminating invasive meningococcal disease in military settings led to accelerated advances in polysaccharide vaccine development against other serogroups of meningococcus and other encapsulated pathogens. As gaps in vaccine efficacy arose over the past half-century, new vaccine technologies and approaches were developed to address the challenges. Several of these, including conjugate vaccines and "reverse vaccinology" led to other novel, successful vaccines that have had a significant, favorable global impact on invasive meningococcal disease. The history of meningococcal vaccine discovery may provide insights into the future of vaccine efforts against other infectious threats.