Immune determinants of COVID-19 disease presentation and severity
Published: January 2021
Journal: Nature Medicine
COVID-19, caused by SARS-CoV-2 infection, is mild to moderate in the majority of previously healthy individuals, but can cause
life-threatening disease or persistent debilitating symptoms in some cases. The most important determinant of disease severity is
age, with individuals over 65 years having the greatest risk of requiring intensive care, and men are more susceptible than women.
In contrast to other respiratory viral infections, young children seem to be less severely affected. It is now clear that mild to severe
acute infection is not the only outcome of COVID-19, and long-lasting symptoms are also possible. In contrast to severe acute
COVID-19, such ‘long COVID’ is seemingly more likely in women than in men. Also, postinfectious hyperinflammatory disease has
been described as an additional outcome after SARS-CoV-2 infection. Here our current understanding of the immunological determinants of COVID-19 disease presentation and severity is discussed, and it is related to known immune-system differences between
young and old people and between men and women, and other factors associated with different disease presentations and severity.