Is that supposed to mean "Probability of CV given Fever is 87.9%" and "Probability of CV given Fatigue is 38.1%"? Those are conditional probabilities, and there are rules for computing with those probabilities.
But you seem to be disputing the numbers themselves. Which is fine, "Garbage In, Garbage Out" as we say, but if you dispute them then there's no point calculating with them.
Campbell Ritchie wrote:... No. If 88% of people with Coronavirus have a fever, that doesn't mean that 88% of people with a fever have Coronavirus.
This falls under the fallacy: I love y therefore y loves me ;)
Also unrelated to the topic ... I'm kind of skeptical as how an excel sheet with a few binary fields can diagnose a disease. Personally, percentage is not a good metric to tell me if I have a disease or not.