Although COVID-19 is very easily transmitted from person to person, the risk of subsequent hospitalization and death primarily affects people who are already at risk because of old age, infirmity and/or chronic diseases such as cancer, diabetes, autoimmune illness, obesity, and heart disease. All of these chronic illnesses are associated with measurable low-grade inflammation in the body. The chronic low-grade inflammation that develops with advanced age has become known as “inflammaging”. Most people with chronic illness unknowingly have low-grade inflammation. Recent research points to a second finding: these same disorders are often accompanied by persistent low-grade anxiety and depression.
All of this as a background increases the danger for a person when acute illness strikes. In addition to the elderly and chronically ill, COVID-19 is causing acute respiratory illness and stroke sometimes leading to death in seemingly otherwise healthy younger individuals. The transition from SARS-CoV-2 infection to diagnosed COVID-19 is typically accompanied by a “cytokine storm.” Cytokines are proteins that are major drivers of inflammation, and their rapid increase, or "storm” is one of the body’s immune responses to acute threat.