Whenever I type the word covid on any web site while using the Firefox browser, it always gets underlined in red to indicate the word does not exist. If the word covid doesn't exist, then covid is not real. Case closed!
Here is a screen shot of the above paragraph before being posted:

So is this to do with a spell-checker?
I haven't had it happen in Firefox.
Maybe it's suggesting you need a capital C?
I use Firefox always, and did not even notice.
The Geeks at Mozilla are likely not that interested in correcting their dictionary, but you can also turn it off and add a default one. Your tongue is firmly planted in cheek, but it is a thread pull on a sweater for Q ! AHHHHHHH!
Adding new words to the en-US dictionary
Not only have they been hell bent on changing the past, but they wanna control the future. We do the exact opposite in every fashion. Get it right, common sense, critical thinking. They are darkness, cover it all up, control the narrative, lie, lie some more. Lie about lying.