second week crash

It has been observed that many people who catch COVID-19 are ill but not desperately so for the first week and then take a sudden turn for the worse in the second week.  This is thought to be the result of the body’s response to the coronavirus. Initially the immune system fights off the virus, in the process producing cytokines, small proteins released by cells to control cellular interaction in the immune and other processes. These cytokines also cause inflammation. Once the virus is defeated the cytokines disappear and, with them, the inflammation. But in some instances the immune system gets it wrong and keeps producing cytokines, creating what is called a cytokine storm long after the virus is gone.  The inflammation is extreme and healthy cells are killed in the process. The most notable patient to experience second-week crash in recent times was Boris Johnson.