It also makes sense as some colds are caused by corona viruses.It makes sense to me. I've long noticed how we tend to suffer one thing at a time, as if what we are suffering protects us against other diseases.
My mother is an example of what I mean. She was one of 13 children in her large family and when young suffered rheumatic fever which caused her heart to be damaged. At 64 that heart was failing with valve disease and a replacement heart valve gave her 14 more years to 78. At no time did she ever have any form of cancer.
All the other 12 children died of cancer in their early 70s and so did their mother**. It appears my mothers damaged heart condition prevented her alone from suffering that fate.
I remember how what made AIDS so puzzling when it first appeared was the way victims could suffer multiple illnesses simultaneously.
** Their father died earlier from the effects of being gassed in WW1.
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Common human coronaviruses, including types 229E, NL63, OC43, and HKU1, usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. Most people get infected with one or more of these viruses at some point in their lives.
https://www.cdc.gov/coronavirus/general-information.html
This has been mentioned from very early in the whole story. With varying degrees of credence.