Do we need the vaccines?
Pandemics have a beginning, a peak and an end, often in the form of a normal curve. If you start vaccinating people at the top of the normal curve, it may look like it is the vaccines that are causing the pandemic to end. A safe vaccine in the beginning of a pandemic may make sense.
An unsafe vaccine at the end is not as good.
Normal distribution curve
Below is a typical curve from CDC for an infection