Does Vivera move teeth into proper position if they have shifted?

Vivera retainers are used for retention.  That is, they help to maintain the final tooth position that the Invisalign treatment achieved.  I would say that as long as the movement since you lost the last aligner is minor, the Vivera retainer will most likely move your teeth back to the right position.  Don't wait too long though to get your retainers in place.  Call your dentist to let them know what happened so they can do their best to expedite the process.  

Vivera was made based on your final teeth positions so it can help reposition your teeth a bit. No active mechanisms but will apply some forces if your teeth relapses or has shifted a little.