Background As soon as a virus enters the human body, it is in a race against time to hijack cells , reproduce and spread . Its survival depends on it, because once the body's immune system detects the intruder a major microscopic war follows. While the Sars-CoV-2 virus behind the present pandemic has killed thousands and spread fear around the world, the immune system that has evolved over millions of years shows no panic. It responds aggressively to eliminate the invader as quickly as possible. At the same time, the virus is trying to disguise its appearance to avoid triggering the alarm system of the immune system — a deadly game of hide-and-seek. That immune system is the reason the human species still exist. Before the war between the virus and immune system at the cellular level , the virus slips into the body, navigating past defenses in the mucus that gathers in noses and throats, on the hunt for cells it can captivate. In the first few hours after the pathogen's ent...