COVID-19 incidence

Like many inveterate news junkies, I’ve had it with COVID-19 case and death counts and flattening of curves. The U.S. has seven times as many COVID-19 cases as European countries but five times the population. The relevant figures are thus 0.5% and about 0.3% of the population, respectively. New cases are dropping in the Eastern U.S. but not in the west. What’s going on?
To understand how severe and lethal COVID-19 really is, we need to know how many have been infected, which, in this equation, is the "denominator." An early study from Stanford of Santa Clara County says we may be underestimating how many cases there already are, which inaccurately gauges COVID-19’s infectivity and eventual mortality.