I took my son to an allergist a few weeks ago. He tested positive for allergic reaction to all types of pollen (possibly with the exception of one) and dust mites. We started shots two weeks ago and look forward to relief. In the meantime he was prescribed Ryaltris which is non formulary and required pre authorization. I'm not sure how we will manage the shots over the summer or Yomim Toivim.
There might be an option that they will give you the vial with the required amounts, and have an EMT or nurse inject it. I've heard ppl do that for the summer.
Yeah I started shots as an adult so this hasn't been personally needed, but in all of the various allergy practices I've been a patient at they have a well-established protocol for sending the serum with college kids when they go off to school etc.
So I'll +1 what Flatbush said
Also, not sure how old your son is but you're doing him a big favor. I jokingly give my parents grief for letting me suffer through terrible allergies for my entire childhood.