Pfizer's vaccine is based on RNA, which is a very unstable molecule that is prone to breaking down. Storing it at -94° F prevents this, but it creates the logistical difficulty of transporting the vaccine.
If Pfizer's coronavirus vaccine is successful, it will be the first-ever mRNA vaccine on the market. How is the vaccine made and how does it work?
RNA-based treatments for select genetic diseases have made major headlines in the last few months by receiving FDA approval and giving hope to families of suffering children.