There are multiple methods for making vaccines, but Pfizer and Moderna use an experimental approach based on Messenger ribonucleic acid or mRNA. It is a simpler, swifter approach to vaccine production, and it was boosted over the clinical finish line by the pandemic.
Vaccination is fundamentally based on “showing” your immune system the disease-causing agent, so it can form a biological memory and be primed to fight it. For many existing virus vaccines, this has meant producing versions or pieces of the virus itself – often snippets of viral protein stripped of their disease-causing ability. These are grown inside chicken eggs, packaged up and injected.
There are now over 150 coronavirus vaccines in development. But Pfizer’s mRNA vaccine was the first to receive emergency authorization by the US Food and Drug Administration, quickly followed by Moderna’s vaccine – less than a year after scientists first downloaded the genome it was based on.