Especially considering several of the actual vaccine candidates were developed in low single digit months, it's the evaluation production and testing that's taking most of the time.

I'm not aware of a single working Covid-19 vaccine, which ones would that be? There are promising candidates, sure, but I don't think any have already been shown to be both effective and safe, which I'd say is required for one to be working, on the timescales that are needed, and I wouldn't know how one might do that so quickly. The current forerunners might well not work out, though I hope at least one of them will work, but my understanding is that anything immunity-related is fiendishly hard.

The one constant in all reporting and discussion about potential SARS-CoV-2 vaccines is wishful thinking. I don't blame the pharma execs for that; talking up their stocks is their job. Everyone else, though, could do with a great deal more skepticism. We'll be lucky to have a commonly-available, somewhat-effective vaccine next year. If you had listened to the cheerleaders in June, you would be shocked to learn we don't have multiple such vaccines now.

Regular mask wearing and careful avoidance of problematic public situations is already more effective than any vaccine for this virus will ever be.