There's already been large scale phase 3 trials, and we've deal with vaccines for decades, they're not entirely novel and unknown each time.
I don’t think that’s accurate in this case. The type of vaccine that J&J released had up until months ago only ever been deployed in animals.
IIRC pigs had a problem with corona viruses that we solved”
The J&J is not a heap of dead virus like the common ones we have had forever. But a live harmless (we think) virus dolled up to look like Rona Corona.
No, there have been no previous live viruses that have been genetically modified to look like other viruses (embedding Covid spike proteins) injected in humans before three months ago in any scale.
We have treated animals with exactly this however, including pigs against piggy rona.
I recommend reading the whole post next time, not just stopping at “live virus”.