H. pylori vaccines: why we still don't have any.

Helicobacter pylori was appreciated as the major cause of peptic ulcers about 30 years ago and the most significant etiological agent in gastric cancer in the mid-1990s. Since that time, progress in the development of a preventive or therapeutic H. pylori vaccine has been relatively slow. The impediments to rapid advances in the field include a luke-warm enthusiasm among clinicians, research scientists, and public health authorities concerning the need for a vaccine, rudimentary understanding of the correlates of gastric immunity to H. pylori and of gastric mucosal immunology in general, the geographical heterogeneity of the H. pylori genome and insufficient pharmaceutical industry support. Recent enhancements in our understanding of the gastric immune response together with advances in H. pylori genomics now provide the potential to accelerate progress in H. pylori vaccine development. Whether an H. pylori vaccine becomes a reality will likely depend upon our ability to appropriately target the populations at highest risk of the adverse sequelae of infection.