It’s not a “unique symptom” of the disease exactly, but health care disasters like we saw later in Lombardy and New York would not have gone unnoticed even if we had no particular virus test.
https://www.washingtonpost.com/national/javits-center-comfor...
> It was only a month ago when Cuomo and New York Mayor Bill de Blasio (D) suggested that the crisis would blow over. But as the need for more hospital beds became clear, Cuomo, at his daily news briefings, described his forceful push on the Federal Emergency Management Agency, and then his calls to President Trump, to allow covid-19 patients at the Javits Center.