This is very helpful from Zeynep Tufekci in her most recent newsletter:
It takes about two-three weeks from exposure and infection to hospitalization, and about four-six weeks to death, sadly. Plus, all early data is subject to selection effects: if the first superspreader events are in, say, college campuses, we get a young cohort who tend to have milder outcomes anyway, so we can’t really get a picture of severity from them easily—severe cases are already rare, so harder to tell the signal from the noise with smaller samples. All this means it may take until the end of December or even early January to get clarity on the question of severity, likely from South Africa and United Kingdom and some European countries with good tracking.
Mark Carrigan 