The U.S. Food and Drug Administration (FDA) has granted emergency use for two new coronavirus vaccines, one developed by the drug company Pfizer and the biotech company BioNTech and the other by the biotech company ModernaTX. Both are mRNA vaccines and have similar structure.

Both vaccines contain modified mRNA that provides the instructions for the synthesis of the SARS-CoV-2 spike glycoprotein antigen. Its mRNA is enveloped in lipid nanoparticles (LNPs) to prevent degradation and enhance uptake into cells.