For many patients, the most severe consequences of COVID weren’t the direct effect of the coronavirus on their lungs, but rather the exaggerated immune response their bodies unleashed to kill the virus. Because the SARS-CoV-2 virus was novel, meaning that human beings had never encountered it before and thus had no established means to combat it, the human immune system tended to overreact. In the most severe cases, it could trigger a “cytokine storm,” a cascading activation of immune cells, which in turn excrete small proteins called cytokines. In the normal sequence of our body’s functions,
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