Advances and challenges in <i>Helicobacter pylori</i> subunit vaccine development: antigen candidates and immunization strategies

Helicobacter pylori, which infects nearly half of the global population, is a major cause of gastrointestinal diseases, including peptic ulcers, gastric cancer, and lymphoma. Current treatment regimens are hampered by antibiotic resistance, high costs, and adverse side effects, highlighting the urgent need for effective vaccines. Several subunit vaccines have demonstrated promising protection or clearance rates in preclinical experiments using animal models, providing a strong rationale for advancing H. pylori vaccines into human clinical trials. However, no vaccine has been commercialized to date, with only the UreB vaccine progressing to Phase III clinical trials. This review discusses recent progress, challenges, and prospects in the development of H. pylori subunit vaccines, with emphasis on antigen selection, adjuvants, immunization strategies, and delivery systems. By evaluating key antigenic candidates and their immunogenic properties, this article aims to provide a comprehensive overview to inform future vaccine development against H. pylori infection.