mRNA Vaccines: Development, Mechanisms and Advances in Delivery Systems

For more than over two decades, mRNA vaccines have been successfully administered and continues to be a promising platform for preventive and therapeutic uses. A key advantage of mRNA-based therapies over DNA-based approaches is that the mRNA molecule only needs to reach the cytoplasm for translation, bypassing the need for nuclear entry. Unlike pre-designed peptide vaccines, which may be restricted to specific MHC haplotypes, mRNA vaccines encode full-length antigens, allowing the host's cells to process and present a diverse array of epitopes suitable for a wide range of MHC haplotypes within a population. The binding of mRNA molecules to pattern recognition receptors enables them to be designed as self- adjuvants, a feature absent in peptide and protein-based vaccines. Since mRNA can encode and produce any protein, it enables the development of preventive and curative vaccinations to combat a range of illnesses, such as infections and cancer, as well as protein replacement therapies. The recent SARS-CoV-2 pandemic underscored the critical need for rapid vaccine platforms, a challenge effectively met by mRNA technology. Companies and research centers have created a variety of SARS-CoV-2 vaccines. These include older types of vaccines, such as those using viruses and proteins, as well as more advanced vaccines that utilize DNA and mRNA technology. This review outlines the recent advancements and advantages of mRNA vaccine technology, including how to design, synthesize, and deliver them to the target cells, as well as the immune system's response to these vaccines.