They were still under 50. Are we saying nobody dies from this under 50 or not? That's the simple question.
Never say never.

It seems there are exceptions to any generalization.
But I think it is disingenuous to 1: Compare health workers in the thick of things with the general population, if for no other reason than guaranteed exposure. and
2: While there will be a small fraction of the population (well under half a percent) who may die, it is likely those people will have some preexisting condition which makes treatment more problematical.
So, let's rephrase the generalization to include only average, ordinary folks who were in reasonably good health living reasonably healthy lifestyles, and we will see the risk to any one person in that age group is statistically very small.
For instance, as of a couple days ago, I read the average age of those who died from COVID-19 was 81.
Youngsters (under 50, and certainly under 30), without preexisting conditions which complicate treatment, seem to do very well against the pathogen.