Illustration of a human ribosome (centre) producing a spike protein (red) from the SARS-CoV-2 coronavirus, the cause of Covid-19. The ribosome is reading a viral mRNA (messenger ribonucleic acid, multicoloured) template in a process known as translation. Once completed the spike protein will be displayed on the surface of the human cell and stimulate an immune response, causing the body to produce antibodies against it. This means that the body is primed to attack the virus should it be encountered after vaccination, preventing disease. The first RNA vaccine approved for human use, developed against the SARS-CoV-2 coronavirus by Pfizer/BioNTech, was approved in the UK on 2nd December 2020.