This chapter sheds light on the milestones and history of mRNA vaccine development. The challenges encountered with an mRNA-based vaccine, and how MERS (Middle East Respiratory Syndrome) and SARS (Severe Acute Respiratory Syndrome) impacted the success of finding quick and effective vaccines, are described. I show how an already existing platform was modified to target the new coronavirus pathogen, and what factors played a crucial role in public acceptance or refusal of the RNA-based vaccines.