Viruses survive outside our bodies because of how they are built. Specifically, they are pieces of genetic material (RNA or DNA) contained in a special coating of proteins called capsids. Viruses cannot replicate unless absorbed by cells in our body. Once a virus is outside the body, its capsid starts to degrade, and the more degraded its capsid is, the less likely it is to survive. When outside the body, these capsids degrade faster in cold, dry environments. They also degrade faster on soft, rather than on hard surfaces. That’s because they need moisture to survive and soft surfaces absorb that moisture.
Drafted: 16 March 2020