You can still carry the virus and be contagious even when vaccinated (apparently).
Not that this matters, though. There have been plenty of threads on here and elsewhere regarding premeds doing shadowing right now. Interestingly enough the admissions officers here seem to be supporting this too, shadowing during the height of a literal global pandemic, while also being MDs, but hey whatever right. Not like we are applying to a field that's relevant to this at all. Totally responsible! Go shadow!
Edit: sorry that sounded rude, if you're set on shadowing now I've heard private or smaller clinics (free even) are letting some kids in. I just had a soft spot for this topic because one of my friends was ignorant and didn't follow safety guidelines while shadowing in November and ended up getting like 15 people in the hospital sick plus literally all of his friends including me + their families, probably legitimately over 100 cases from that one kid shadowing in the ER during covid for some F'in reason. And the pandemic is worse now.