Sure, in isolation, that's all true. However, in isolation, the cost of doing nothing is zero. In a pandemic where 70% of America will catch a disease somewhere between 0.3% and 1% fatal, the cost of doing nothing is dramatically higher than zero. In fact, it's dramatically higher than a vaccine that just randomly kills 1 in 1,000,000 people - which this one strictly does not.

My point is that yes, an investigation should be carried out, but stopping the trial obviously - trivially - does more harm than good due to the extenuating circumstances of the global pandemic.