Last regular flu vaccine was done with a self retracting needle. I prefer those, and here is why

Humans move when inserting the needle. The syringe moves when it’s injecting (not a limit, but a little). The spring assisted retract means reduced damage when the needle is removed

Less bruising. Less pain. Less discomfort and zero risk of any blood borne pathogen infecting the medical professionals, as the part that was sub dermal is retracted into the body of a single use syringe