Extensive research around mRNA vaccines and their proposed utility during the current COVID-19 pandemic resulted in many publications concerning the SARS-Cov-2 spike protein and angiotensin converting enzyme-2 receptor-binding domain of the virus, but none describe the characteristics of the full-length protein obtained from the modified/synthetic mRNA that is part of the Moderna and Pfizer-BioNTech vaccines. In this paper, we provide the first data characterizing the actual proteins produced by mouse and human cells in culture that had been incubated up to 30 minutes with the commercial vaccine produced by Moderna (i.e., Spikevax). The mRNA vaccine continues to produce proteins up to 12-14 days after introduction to the cells. The molecular weight of the SARS-CoV-2 encoded protein ranges from 135-200 kilodaltons depending on the extent of glycosylation.