成人快手

Two vaccines have been developed that show promising interim results. Both are RNA vaccines - which involve injecting part of the virus's genetic code into the body in order to train the immune system. The vaccines have to be stored at very low temperatures: Pfizer and BioNTech's vaccine at around minus 80C and Moderna's at minus 20C.

Daniel Anderson of Harvard MIT Health Science explains why some RNA vaccines have to be kept at ultra-cold temperatures, while others can be stored in a refrigerator.

(Image: Close-up of a gloved hand holding a phial of trial vaccine BNT162, Credit: BioNTech SE 2020.)