Sarah Zhang has a great piece in The Atlantic about the two vaccines announced this week:

Both vaccines, from Moderna and from Pfizer’s collaboration with the smaller German company BioNTech, package slightly modified spike-protein mRNA inside a tiny protective bubble of fat. Human cells take up this bubble and simply follow the directions to make spike protein. The cells then display these spike proteins, presenting them as strange baubles to the immune system. Recognizing these viral proteins as foreign, the immune system begins building an arsenal to prepare for the moment a virus bearing this spike protein appears.

It’s truly amazing that almost exactly a year since the virus was first diagnosed, and only nine months after the DNA of COVID-19 was sequenced, we have a viable vaccine. Two actually! Not only that, no one was quite sure the mRNA approach would even work — this is cutting edge science based on years of research, but it is an entirely new approach. What a testament to human ingenuity!