At this stage of the pandemic, there's a handful of vaccines being administered to the population, each with its own unique formulation. Pfizer-BioNTech and Moderna, the only vaccines approved in the U.S. and the E.U., are both mRNA vaccines, meaning they contain a piece of genetic code that instructs cells to produce a harmless viral protein that primes the body against the virus when it encounters it in the real world. The vaccines also contain fats, salts, and sugar to stabilize the mRNA and help it enter the body effectively. Read the full article