I agree with you when you claim that this is the fastest vaccine ever made. But that doesn't necessarily mean that the quality checks and the clinical trials were skipped. All the vaccines have either completed their phase III trials, or they are in the process of wrapping them up. All of them have completed the Phase I/II trials many months ago. Now this is important because if a vaccine has passed the Phase I/II trial, it means that that particular vaccine is safe for administration on human body.