My understanding is that both the Moderna vaccine and the BioNTech one are being made in only a couple sites each.

Is there any reason why more labs across the globe couldn't start producing the vaccines, under a license from those companies? Is the technology needed to create them so unique that it literally can't be made anywhere else?

In this particular case the mRNA technology Moderna (and Pfizer) is completely new, these are the first two vaccines approved. Yes they spent a lot (including OWS money) to ramp production, all previous mRNA vaccine production was <1M doses per year in 2019 and before. So between Moderna and Pfizer, we are looking at probably 1.8 billion - 3 billion doses produced.

There are many genuine complaints about the vaccine ramp up, but this is one of the few cases where these numbers are a "good job".

This is why its so important for the FDA to give EUA to Astrazeneca now, that is a technology that can be scaled quickly. They should also encourage a readout now of J&J, which is almost certainly over the efficacy threshold and can also be scaled. With these two approvals, we can have enough vaccine for a 1st dose for everyone within the next 60 days.

The Sputnik adenovirus vaccine is easier to manufacture and they are allowing some countries to install their own capacity. I don't know if they improved the accuracy of their tests, they were kinda sketchy when they announced it.

The PR and marketing is not targeting the US for some reason, maybe because they think no one will want a "Russian" vaccine in the US or maybe because it's more expensive... but in other countries it's going to be "the" vaccine, so I hope it works.

They would need to do an FDA supervised trial.

Edit: the Oxford AstraZeneca and J&J vaccines are adenovirus and are nearing completion of their trials, so we are on track for much wider availability.

I suspect that the Chinese vaccine will be the most used outside of US and Europe.

It's more the difficulty in standing up a new site for GMP (good manufacturing practice). Closest analogy in the tech word would be standing up a new fab, but quite a bit cheaper. It takes time to iron out all the kinks and show that everything is being produced correctly and safely. And skipping this would be disastrous, since we are already reaching dangerous amounts of vaccine hesitancy.

That depends on what the bottleneck is. If it's a precursor or component then more sites won't help at all. Others have commented that it's either vials or clotting factor.