It's mostly funding, manpower and bureaucratic shortcuts that account for the speedy development of the Covid-19 vaccines. Cutting through all that red tape is probably the biggest factor.

In theory most vaccines could be developed within a timeframe like this, but since they normally have to compete with each other (and non-vaccine related health research) for resources and bureaucratic attention, they're not.

I could understand being wary of vaccines developed in Russia or China, since they have a history of poor transparency and corruption, but there's very little reason to distrust the current wave of vaccines coming from established universities and pharma corps.

And I'd take the opinion of currently working experts in the field over that of a single retired prof. I find that's generally a good strategy to end up on the right side of history, so to speak. Because there's always a retired dude with a degree willing to co-sign some dumb shit somewhere.