COVID-19 is triggering mast cells that are reacting to the virus and creating a hyper-reaction of the immune system, called Mast Cell Activation Syndrome (MCAS).
MCAS is a condition in which it affects more than one organ in the body. Mast Cells were first named and discovered in 1878 by German-Jewish Nobel Prize winner, Paul Ehrlich, a man of modern immunology.
Mast cell activation syndrome is an immune response that can actually harm the body. Hyper-responsive cells or over-reacted cells that are usually triggered by a virus can do this to the body. This is what is happening to some who contract mild cases of COVID-19.