StealthX: A Versatile and Potent Exosome-Based Vaccine Platform for the Next Pandemic

Exosome-based vaccines represent a transformative platform in modern vaccinology, combining nanoscale delivery, biocompatibility, and potent immunogenicity. Among these, the StealthX platform developed by Capricor, Inc. has demonstrated exceptional versatility, enabling antigen presentation at nanogram level doses without the need for adjuvants. Preclinical studies using StealthX have shown strong humoral and cellular immune responses against SARS-CoV-2 variants, including Delta and Omicron, as well as broader applications against influenza and RSV antigens. The platform's ability to accommodate multiple antigens within a single formulation addresses the challenges of viral variation and facilitates multivalent "mix-and-match" immunization strategies. This review offers an in-depth evaluation of the StealthX vaccine platform, covering the biological mechanisms underlying exosome function, the engineering approaches used to load antigens, and preclinical results demonstrated across three pivotal studies. By synthesizing current evidence, this review underscores the platform's applicability for emerging infectious diseases and explores the strategic value of multivalent exosome-based vaccines in global immunization efforts as an emerging next-generation vaccine technology.