system
Given the following post, respond as if you're commenting on Reddit:
human
Why does COVID-19 affect people differently?

This may have been asked here before, but I’m trying to understand how a virus can show completely different symptoms in one person versus the next. For example, Donovan Mitchell, a NBA shooting guard for the Utah Jazz, tested positive for COVID-19 a week and a half ago. He’s repeatedly stated that he is completely asymptomatic and is feeling better than ever, even stating the he would be able to play in a 7-game series right now. But then I see stories of people in their mid-20’s (around the same age as Mitchell), who appear relatively healthy, having to be put on respirators and checked into ICU. I’ve never heard of a virus affecting people completely different like this. For example, if two people around the same age and health get the flu, it usually affects them about the same. And even if it’s not exactly the same, they both would experience negative symptoms to some degree. Why is COVID-19 so different? Any explanation on this would be appreciated! Thanks!
gpt
Physician here. The answer is the genetics and experience of your immune system. In layman’s terms there are two important decisions your body must make. The first is how aggressively does the body want to fight the virus when it initially enters your body.  Usually this is at the level of your throat before it gets into your lungs. If your body succeeds in fending off the virus at this level, you will have mild to no symptoms. If your body fails to fight off the virus at this level, it will enter your lungs. This second part is where your body has to walk a fine line. There is a degree of variability of your immune system to decide how much “ammo”it wants to throw at the virus. If your immune system is filled with accurate snipers you will have no problem clearing the virus from your lungs. Now if it panics and starts throwing  grenades at anything that moves, it will kill much of your healthy lung tissue and clog up the airways with fluid causing you essentially drown yourself. Of course you might be saved if you medical professionals stick a tube down your throat and connect you to a machine that forces air into your lungs for days. There’s is nothing you can do to improve the accuracy or measured response of your immune system.  Covid 19 is no joke. We’re all playing Russian roulette when we make contact with others.