There is no autofocus on an MV12 (fixed lens). But good thinking.
Can you see anything unusual when you visually inspect the camera?
I think I would take a gentle cloth (maybe microfibre) and try cleaning the lens. I am most suspicious that something has gotten on it.
Being in a medical setting, it's possible that some chemical has been heated, vaporised, and re-condensed on the lens.
Next thought, in desperation, try to power cycle the camera (unplug it and plug it back in again).
Next thought, in even more desperation, try upgrading the firmware.

Trying to think more laterally - image quality is affected by lighting. Does it make any difference if you turn more lights on (if that is even an option)? Is there any chance you are using less lighting than before?