The formulation and the technological advancements in RNA biology, chemistry, stability, and encapsulated delivery systems that have enabled the development of fully synthetic mRNA vaccines are discussed in this volume. The applications of the mRNA technology is covered, focusing on infectious diseases but also touching on other indications, such as immunotherapies and molecular therapies. Potent and long-lasting immune responses observed in animal models, encouraging data from early human clinical studies, together with the success of two mRNA-based COVID-19 vaccines support the use of...