I doubt the internet would present this information now very easily, but after "COVID" kicked off I did a digg on "anosmia" or loss of the sense of smell. This was a prime symptom of "COVID" you may recall. I was surprised to learn that a lot of people lose their sense of smell and the most typical cause was "the common cold". The site I looked at said that people didn't often know that this could be a consequence of a cold. Personally, I think this was the precise reason it was used to tell people they had "COVID". The symptom was unusual enough for people to consider it abnormal but not commonly known.