I was diagnosed with vertigo a week ago it has not gotten any better. how long does it normally take to go away? also the meclazine i was prescribed is not working. could it be related to the moderna shot i got 2-3 weeks ago?

Moderna vaccine is a mRNA vaccine, not a live attenuated vaccine, so it less likely causes viral vestibulitis (with vertigo is the main symptom); however, this type of vaccine is still relatively new so the definite answer for your question is still unknown. If vertigo has not improved after one week and Meclizine is not helpful you may need CT of the head if it was not done last week.

Skeptical of vaccine reaction causing your vertigo, but cannot fully exclude, as the timing is suspicious. But the vertigo should start resolving, if a typical viral labyrinthitis, at 7-10 days, yet other causes could be considered. Since you remain symptomatic without help from current meds, have your doctor reassess the entire situation.