A new USC study suggests that temporarily suppressing the body’s immune system during the early stages of COVID-19 could help a patient avoid severe symptoms. That’s because the research, just published online in the Journal of Medical Virology, shows that an interaction between the body’s two main lines of defense may be causing the immune system to go into overdrive in some patients. USC notes that the body’s first line of defense, the innate immune response, starts right after an infection, like an infantry going after a foreign invader, killing the virus and any cells damaged by it. The second line of defense, the adaptive immune response, kicks in days later if any virus remains, employing what it has learned about the virus to mobilize a variety of special forces such as T cells and B cells. The researchers say that unlike the common flu, a fast-moving infection which attacks certain target cells on the surface of the upper respiratory system and kills almost all of the target cells within two to three days, the COVID-19 targets surface cells throughout the respiratory system including in the lungs, and it has an average incubation of six days and a much slower disease progression. This leads the adaptive immune response to kick in before the target cells are depleted, slowing down the infection and interfering with the innate immune response’s ability to kill off most of the virus quickly.