NF38

While aura's protective properties shield individuals from physical harm, its protection does not extend to ailments of a biological, psychological or toxicological nature. This can be tested and seen in everyday life, as even those with prodigious auras suffer from illness, stress and the effects of alcohol.

"Huh, I guess that explains why I could still be drugged." Then again, if aura didn't work that way, there would be no medical treatment beyond bandaging a wound and hoping for the best.

While those with aura can contract illness, it's worth noting that even in the most extreme and life-endangering cases, a person's aura does not suffer. In the same way aura offers no protection against illness, illness does not drain aura in turn. Naturally, this is of little benefit to those about to die, but does work to remind huntsmen that even when badly ill or suffering an infection, they can still rely on their aura in the event of a Grimm attack. There were a few annotations and citations to follow that up, all related to research he made a small note to check out if he got desperate.