There were side effects that were serious. The vaccines and boosters effected different age groups differently. Some age groups were more likely to develop serious side effects.

Covid effected different age groups differently. Some age groups were more likely to develop serious complications.

In the instances where the risk of serious side effect was more likely than the risk of serious complication, at least one of the boosters was more likely to be bad for the patient.

If it is more likely to cause harm, I can understand not wanting to take that version.

My point is it’s ok to refuse medicine based on medical evidence.