It's both. Ramping up testing which is giving a view into the impact of the previously underestimated exponential growth. The low CFR rate is simply time. It t

It's both. Ramping up testing which is giving a view into the impact of the previously underestimated exponential growth. The low CFR rate is simply time. It takes roughly 3 weeks from infection to death. Meaning deaths should be compared with count of infections 2-3 weeks ago to calculate CFR. Separately, there likely were a number more than died from it previously that didn't get testing because testing was so hard to come by (and the scope of the spread was not yet understood). If NYC hospitals get overwhelmed like they are possibly on pace to, don't be shocked if you see CFR rise up to 4-5%. Especially as growth in new cases no longer out strip existing (which suppresses naively calculated CFR).