An mRNA vaccine describes a specific mechanism for making a protein in our cells. The blueprint for the protein to be produced in our cells is injected into our bodies. The technology behind this is not new. In 1959, researchers discovered that our cells contain single-stranded ribonucleic acids, which contain the genetic information to build proteins. In 1989, it was possible to inject specific sections of RNA, called mRNA, into cells for the first time. In the 1990s, it was possible to induce an immune response in mice using RNA. RNA vaccines were first tested on humans in clinical trials in 2002. The decisive breakthrough was finally achieved by Hungarian biochemist Katalin Karikó. Together with fellow researcher Drew Weissman, she managed to package sensitive mRNA into lipid molecules. Such tiny nanoparticles can be injected into animals and humans without causing a dangerous immune reaction. This allowed mRNA to be used in therapy and laid the foundation for an mRNA vaccine. (dhr)