> The 12 billion or so COVID vaccine doses given also only have a history of ~2 years. If the adverse effects of it were say for instance, minor cardiac damage that resulted in no acute symptoms, but instead an overall reduction in life expectancy by 5 years, the costs of such would not be known for some time.

Can you explain how this standard of rigueur leads to anything less than a complete halting of medical research?

The original trials for the Pfizer vaccine were conducted on 46k people (half of which necessary recieved a placebo). At the time of those trials there was no shortage of willing volunteers to take part in the trial, no limit on the amounts of funding available and a considerable appetite to do something. Other trials have to make to with much fewer participants with hundreds to low thousands seemingly typical.