Opportunities and Challenges of mRNA and VLP Technologies for Pan-Flavivirus Vaccine Development: Focus on Conserved Quaternary Epitope Conformations.

Mosquito-borne flaviviruses, including Dengue virus (DENV), Japanese encephalitis virus (JEV), West Nile virus (WNV), Yellow fever virus (YFV), and Zika virus (ZIKV), continue to present a significant threat to public health worldwide. In 2024, these viruses accounted for 11,717 reported cases in the United States and more than 7.6 million cases globally. As of early 2025, according to CDC data, 1830 cases of dengue had already been reported, with 1584 transmitted locally within the U.S. Despite the considerable burden that these diseases pose, no specific antiviral treatments exist. A very limited number of virus-specific vaccines have been licensed, such as those for YFV, JEV, and, with specific constraints, for DENV. To date, no pan-flavivirus vaccine is available. This review examines the potential of emerging vaccine platforms-particularly messenger RNA and virus-like particles-as promising tools in the pursuit of a broadly protective flavivirus vaccine. We analyze current strategies for inducing cross-neutralizing immune responses and discuss how these technologies could support the presentation of conserved quaternary epitope conformations, which are increasingly recognized as critical targets for establishing potent immune responses. We review key advances in virology, immune response, and immunogen delivery systems to highlight the potential for developing a pan-flavivirus vaccine.