‘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... This overall process mimics the steps of infection better than some traditional vaccines, which suggests that mRNA vaccines may provoke a better immune response for certain diseases...
‘All of this is how mRNA vaccines should work in theory. But no one on Earth, until last week, knew whether mRNA vaccines actually do work in humans for COVID-19. Although scientists had prototyped other mRNA vaccines before the pandemic, the technology was still new. None had been put through the paces of a large clinical trial. And the human immune system is notoriously complicated and unpredictable. Immunology is, as my colleague Ed Yong has written, where intuition goes to die. Vaccines can even make diseases more severe, rather than less. The data from these large clinical trials from Pfizer/BioNTech and Moderna are the first, real-world proof that mRNA vaccines protect against disease as expected. The hope, in the many years when mRNA vaccine research flew under the radar, was that the technology would deliver results quickly in a pandemic. And now it has.’
Read here (The Atlantic, Nov 19, 2020)