mRNA-1273 is synonymous with the Moderna mRNA Covid-19 vaccine. The Moderna mRNA vaccine was produced from theoretical design to finished product and distribution in less than one year. This was the first published paper on that vaccine. It was first posted online on 12-30-20, updated on 1-15-21, and published in print on 2-4-2021. The vaccine was initially administered under "emergency use authorization" granted by the U.S. FDA.

This vaccine delivers the mRNA needed to code for the pre-fusion stabilized S (spike) protein to the inside of the host cell inside an encapsulating hollow lipid nanoparticle. That mRNA then instructs the host cell to produce S protein molecules which are then ferried out of the host cell and act as the antigen/immunogen for this vaccine once outside of the cell.

(Thanks to Juan Weiss for this reference and its interpretation.)