Why do clinical trials when you can do live trials for free. Just wait a few month and look at the situation in France.
France bought a huge stock of Moderna but people there only want Pfizer, so now they have a huge stock of Moderna and a shortage of Pfizer. So to re-balance their inventory they decided that people over 30 can no longer have the choice of what vaccine they get.
And they have also recently speed-up vaccination effort by requiring to have a less than 7 month injection/contamination after January the 15th or be severely constrained in daily life. So in about two months, you'll have a huge influx of guinea pigs data.
So if you just turned 30 and never vaccinated you are up for the Moderna huge dose that they tell you they consider not safe for people a few days younger than you are, (and the dosage was probably too heavy because it has now been reduced for the boosters).