question about shots

Hello Dr. I am 24 years old and i live in Phoenix AZ. A couple of weeks ago i went to my regular family doctor and i was given a tetanus shot. My actual Dr. didnt give me the shot but it was like a medical assistant or something. Anyway while i was getting the shot i remember hearing like a popping noise. I have OCD/HIV phobia and i am currently going through counseling about it and today i started getting scared about maybe the lady used a used needle on me when i got my shot in my arm.  Do those tetanus shots already have the stuff inside the needle or the sharinge, i am just wanting to make sure that it was a brand new needle or a new shot but also i want to know what that noise was as well, as a medical dr and someone who has way more time with needles than i ever do is that a customary noise. I didnt even think to ask when i heard it but i just assumed it was something like a noise the needle makes when its brand new and it was like a safety thing or something.  i dont know if this all makes sense or not and i know i heard like a popping noise or something while the needle was still in my arm. Like i said i dont know about shots and needles and i thought that once she put the needl in my arm then she poped like a safety thing that would allow then plunger on the sharinge to be pushed down to give the shot. i dont know can you please answer.

[Kevin Pho, MD]

I wasn't present during the shot, and I can't comment exactly on what the popping sound was.

Typically a new syringe and needle is used for each tetanus shot.  Sometimes, they are equipped with safety devices, which may be the source of the extra sounds that you heard.  

Different clinics use varying needle systems that can cause a variety of noises during the shot.

Followup with your personal physician is essential.

This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.

Kevin, M.D.
www.kevinmd.com