mRNA and DNA vaccines mimic infection by delivering instructions to build viral proteins to recipients’ cells. There currently are no vaccines in either of these categories that have been approved for use in humans. This has not deterred ModernaTx, a US-based company that is working in collaboration with the US National Institute of Allergy and Infectious Disease to develop a mRNA vaccine to prevent the entry of the COVID-19 virus into human cells. This vaccine has bypassed all studies in animals, instead jumping directly into a Phase One trial of 45 participants. A Phase Three study of 30,000 participants in the US is now in progress.