Basically, throughout the whole run, you cannot take damage. "Damage" in this game would be any time where the germ is surrounded with a yellow outline and loses energy. So that means soap and mouthwash would not count as damage since you don't actually lose energy. Let me know if you would want this to become a category

This is the first WR, by NoiceName. In crumpet bloodstream he avoids the B-cells and macrophages in the beginning but gets hit by them later which could mean that damageless is possible.

Cool