I think that the prisons will be a place of suffering. Anti vaxx are usually seen as spreaders of misinformation. Thus, the prison directors could easily perform experiments on them, rape them, poke out their eyes etc. and the general public would believe that those were just lies and self inflicted wounds.Assuming the government actually honors its statement to release you after 4 weeks, you are still required to get vaccinated or eventually be arrested again.
Effectively, this is get vaccinated or face life in prison. Assuming it's not a bluff. It may take some time for them to really get down to enforcing all of this, but nothing I've seen from the oligarchs in the last 2 years leads me to believe they are bluffing. It should be painfully obvious by now that they are all-in and going for their new world order.