Find me a newspaper article (not medical!) where it's used. "When my wife was pregnant, I was seeing gravidas everywhere"... ever heard anyone actually talk like that?

OK, but you're changing the rules as you go. At first there was no such noun. Now it has to be used without explanation in a newspaper. There are lots of words that won't be used in a newspaper. For example, "T-SQL" is unlikely to be used without explanation in a newspaper. Does that mean it isn't a noun?

But it's a real trouble when there's no word with the desired meaning as its primary meaning. Whatever you choose, you're running on a secondary or worse.

So you use two words, or use an adjective and save an article (not she is a "sickperson" but she is sick) or choose a more specific noun of which there are plenty in medical English. ;-)

Except when the context consists of similarly ambiguous words, when you have a real misunderstanding in the works. Happened to me several times here.

I think you do OK ;-)