Severe COVID is inflammatory in nature. Most people's immune systems work properly, and they have a typical cold / flu experience. The spike proteins cause some folks' immune systems to go haywire, though. Since the virus tends to bind to receptors in the lungs, lung inflammation is a common complication. The virus can cause inflammation anywhere, though, which is why there's the rare possiblity of heart damage, nerve damaged, etc.

Anti-inflammatory drugs, aka immune system suppressants, chill out folks immune system. Taken to an extreme and you'll be injured by the actual virus. For folk prone to inflammation, though, a bit of suppression helps keep things from going haywire.

This is my personal reservation about the mRNA shots. The whole point is to inject spike-building mRNA into your body, so that your own cells produce the spikes. For people prone to inflammation from the spikes, it effectively gives you an auto-immune disease. On top of that, the shot can easily go into your blood stream, and then get absorbed into your heart muscle. So, the shot is only effective in avoiding severe complications from COVID in that, in the population of people that would have had severe COVID, it preemptively causes severe complications from the shot instead... in their heart. It's irrational and irresponsible to expect folk to inject themselves with a compound designed to cause an auto-immune disease.