The modeRNA vaccine is an mRNA vaccine, a completely new type of vaccine. While theoreticall less likely to have adverse effects, it did have adverse effects, and its efficacy remains a question. These are completely new types of vaccine, that presumably would need even more testing than the relatively well understood attenuated viruses.

> modeRNA

I can't believe I didn't notice that until now.

> completely new type of vaccine

Then is it a vaccine at all? Vaccines were traditionally live, dead, or attenuated virus/bacteria injections, some with adjutants, to stimulate an immune response.

Technologically speaking, it's bicycle vs airplane. Similar underlying purpose, entirely different implementation.

Both a bicycle and an airplane are transportation vehicles. Likewise, anything that illicits imunity is a vaccine, regardless of how novel the approach is.

Every time we see or hear an expert on the topic of COVID-19 vaccines, she/he is either circumspect to the point of pessimism (this is rare, but see e.g. Robert Gallo) or obviously trapped in a spiral of wishful thinking (this is common). We've never made anything like this hypothetical drug. Forget about election day. I'll be surprised if we have a commonly-available and effective COVID vaccine in 2021.

Not the question you asked but the Chinese company Sinopharm has started phase 3 trials of a classic inactivated virus vaccine (and Bharat Biotech is starting phase 2 trials as well in India). The difficulty will be mass-producing it, of course, but we aren't necessarily reliant on novel vaccine technologies.