Every sick child, and probably every adult at some point, asks that existential question: why am I suffering? 

No answer is satisfying. To be sick is to feel vulnerable, weak, not in control, not in the game. Life is chugging along outside of your room. You can hear laughter, cars going here and there, people out and about. But you are stuck, shivering under blankets, appetite disrupted and struggling to remember what it was like to feel healthy. 

With fever, all of this is worse because the capacity for one's brain to process information with full rationality is deprecated. High fever can induce a form of brief insanity, even involving hallucinations. You imagine things that are not true. You know that but can't shake it off. The fever breaks and you find yourself in a pool of sweat, and your hope is that somewhere in this mess the bug has left you. 

For children, it is a scary experience. For adults too, when it lasts long enough. 

From the depths of the suffering, people naturally look for a source of hope. When is recovery? And what can I expect once that happens? Where is the meaning and the purpose behind the ordeal? 

For a conventional respiratory virus, and for many other pathogens, generations have known that there is a silver lining to the suffering. Your immune system has undergone a training exercise. It is encoding new information. That is information your body can use to be healthier in the future. It is now prepared to fight off a similar pathogen in the future.