There is a common misconception that long term effects will manifest long after the injection. All vaccines with longterm effects manifested their effect shortly after the injection. It makes little sense that you will have adverse reactions months or years later because the compounds are long gone from your system.

There are lots of things that do damage that isn't necessarily obvious in the short term, especially if you don't know exactly what that damage might look like. There's a reason I said we probably made a good bet with mRNA vaccines for COVID, the odds that they've done some kind of damage that isn't immediately apparent and we'll see an uptick in some problem or another a few years down the line in vaccinated people is very low but not zero. If the risk of this vaccine damaging patients in some fashion that wasn't apparent within the duration of trials was zero, rather than merely low there would be no reason to make the manufacturers immune to liability from damages caused as a consequence.

On the upside, we conveniently have a large population who have decided to be the control group for mRNA COVID vaccines out of political spite so we have a large sample to compare long term outcomes between.