I like your point, though if we're talking about the overall disease fighting system, it is the evolutionary oldest part that handles the initial inflammation,

I like your point, though if we're talking about the overall disease fighting system, it is the evolutionary oldest part that handles the initial inflammation, nasal drip, and fever. The later part, the adaptive part, the part actually works on the principle of immunity, gets going later, and once it has asserted itself, then you feel relief, at least in part because that primitive initial reaction begins to recede.