Studies in animal models have demonstrated prophylactic and therapeutic immunization against H. pylori, the causative agent of peptic ulcer and the major risk factor for gastric cancer. Vaccine candidates are in development and clinical trials are planned . The convolution of H. pylori with the human races has resulted in variation in strain genotype, immune response and disease progression which may compromise global vaccine efficacy. Here we address three fundamental questions relevant to a vaccine capable of conferring global protection :
1) Can antigens capable of conferring global protection against geographic strain variants be designed,
2) Can correlates of protection based on cytokine expression and immune system polarization be defined and
3) Will concurrent infection with strongly immune polarizing pathogens compromise vaccine efficacy. Parallel studies in Europe and in China, where over 80% of the population is infected, are planned.