One factor speeding up the phase 3 trials is the high rate of infections. Since the evaluation is done at a set number of confirmed cases among the test subjects, this happens much sooner for covid than it would be for just about anything else at this time.
Another factor is money. The covid vaccine trials have done some testing steps in parallel that would normally be done sequentially to avoid wasting money should it fail along the way. So yes, more risks are being taken, but they are financial, not clinical.
Another factor is money. The covid vaccine trials have done some testing steps in parallel that would normally be done sequentially to avoid wasting money should it fail along the way. So yes, more risks are being taken, but they are financial, not clinical.