GenIV vaccines: bridging innovation to equity in neglected tropical diseases.

Recent breakthroughs in molecular vaccinology have defined a new generation of vaccines that integrate synthetic mRNA, self-amplifying RNA, and nanomaterial-based platforms. These fourth-generation vaccines offer exceptional adaptability, rapid design, and strong immunogenicity, as demonstrated during the COVID-19 pandemic. Their potential now extends to neglected tropical diseases (NTDs), where conventional vaccine strategies have failed to deliver durable protection. This review traces the evolution from whole-pathogen to precision molecular vaccines, highlighting the mechanisms, delivery systems, and translational advances that underpin the GenIV paradigm. Using leishmaniasis as a case study, we discuss how these technologies can bridge innovation and equity through technology transfer, regional manufacturing, and global collaboration. By integrating scientific, ethical, and implementation perspectives, this work outlines how next-generation vaccines can transform both epidemic preparedness and the equitable control of endemic diseases.