What's the lower bound on vaccine development? Toby Ord writes in a recent post:

The expert consensus was that it would take at least a couple of years for Covid, but instead we had several completely different vaccines ready within just a single year

My intuition is that there's a lot more we can shave off from this. The reason I think this is because it seems like vaccine development is mostly bottlenecked by the human-trial phase, which can take upwards of months, whereas developing the vaccine itself can be done in far less time (perhaps a month, but someone correct me if I'm wrong). What are current methods to accelerate the human-trial phase so it's down to a handful of weeks, rather than months?