What's different about this latest vaccine? The Pfizer-BioNTech and Moderna vaccines are made using messenger RNA, a technology that gives instructions for making a harmless piece of what is called the "spike protein." The spike protein is found on the surface of the virus that causes COVID-19. The proteins made with the mRNA instructions activate the immune system, teaching it to see the spike protein as foreign and develop antibodies to fight it. The vaccine by Janssen Biotech, owned by Johnson & Johnson, uses a different approach for delivering the genetic instructions for creating the coro...