This first link is to an article maintaining that there is good evidence that we don't get a cold and the flu at the same time:https://www.healthline.com/health-news/you-wont-get-flu-and-cold-at-same-time" ... Its (the study's) conclusion was that there is strong evidence the viruses that cause colds and influenza interact — and interfere with each other — in the human body."
and " ... having the flu prevents or delays the onset of a cold, and vice versa."
As is often the case, the article says more research is needed to discover the exact mechanism for how this works, but it also maintains that knowledge gained here might be useful in creating an artificial process that mimics this natural one, and thus prevents colds or flu from developing in the first place.
I had personally always thought that this was the case, that we don't get both at the same time, but it's most interesting to see that there may actually be scientific evidence that this is so.
It also sort of suggests, and I'm only speculating here, that maybe cold and flu microbes are actually much more territorial than we may have thought, and that when they enter a host, they do something that "stakes out the territory" for themselves. Perhaps they do something like releasing a chemical as soon as they enter a host that repels other invading microbes, making it harder for the second-comers to get a foothold. Maybe research will show it's something like that. Fascinating stuff!
And it also leads to a most ironic situation that is very likely taking place everywhere right now. That is, there are some people walking around right now, coughing and sniffling, terrified that they have coronavirus, when in fact what they have is a common cold that is actually protecting
them from CV! Ironic indeed!
Anyway, it's certainly most interesting if this claim about
cold and flu microbes not occurring in us simultaneously is indeed the case, and knowledge of this fact could for many play a part in how they deal, at least psychologically, with CV in their lives right now.
Here is the link to the actual study:https://www.pnas.org/content/116/52/27142.full