A week ago i got the vaccine against covid 19. during the vaccination process the nurse did not open a new syringe in my presence which made me think that she may have strained the syringe to another person or if the nurse herself is infected and may?

Either it’s a multi-use vial (all are) or she’s “harvesting” your blood to use again. Was she wearing a long black cape?

In regular times, practitioners do not need to open a new syringe and needle in the presence of the patient. The practitioner shall do the right thing. The patient shall trust that the practitioner did the right thing. Otherwise, we have a humanity problem, not a medical practitioner problem. In pandemic times, I expect that new syringes are being filled 5-20 at a time from multi-dose vials.

First, I agree fully with my colleagues, as odds are that all was done properly. Not clear why you have your concerns. Suggest you talk to facility personnel and express the opinions provided herein, and get their response, directly.