No serious scientist is going to give an untested drug to millions of people. There are over a hundred vaccines in development, of which two or three have been

No serious scientist is going to give an untested drug to millions of people. There are over a hundred vaccines in development, of which two or three have been successful. Yes, it seems like the success rate may be higher than for "regular" drug development. But, crucially, nobody knew this. There haven't been a whole lot new vaccines developed in the last few decades. Besides, as far as I know production capabilities were being built and stockpiles created while the trials were ongoing.