Got my booster in December, was exposed to someone in late January (helped them with their covid test as they coughed on me), and never tested positive from that
Was literally inside for 1 minute picking up food the other day without a mask on, and just tested positive with a fever and heavy cough
My point of this (anecdotal) story is it seems like they were right when they said vaccines only last about 4 months
Hopefully they can figure that out...