In many countries – at least in Europe and North America – a large proportion of the population has been vaccinated against COVID-19. In Denmark, the vaccines that have been used are the ones from BioNTech/Pfizer, Moderna and AstraZeneca (the latter has however been discontinued). The two first ones use mRNA-based technology – the last one vector/DNA-technology. But how do they actually work? And what are the differences – and similarities? Watch this animated explainer, that I have made in collaboration with the genetics expert Lasse Folkersen.