Help me out, as I really can't grasp how this is good news (except in the sense it could be worse). First, "death rate" isn't "morbidity rate".
Wikipedia says (yesterday) 257,216 confirmed cases (1.25% of the population) and of those 15,302 people have died. That's 6% morbidity rate. I think the 0.5% "death rate" is based on 20,000,000 x 15% with antibodies x 0.5% = 15.000. So 0.5% is the death rate from people who've had it and people who've not had it but have antibodies (morbidity is deaths relative to cases).
15% in New York have antibodies (if the test is accurate); that might suggest that 11 out of 12 people who have coronavirus antibodies didn't catch Covid (were those with antibodies asked about symptoms?) and perhaps the vast majority might not even have noticed.
Let's assume antibodies do mean you can't get it again. Let's say a similar number have natural immunity (without producing antibodies). That would be 30% of the population. But that may mean at least 14 million people in the State haven't been exposed to the virus and are still at risk - and, 35,000 more might die. Unless you can test how many people have actually avoided infection when they were exposed to the virus, that's a lot of people to go before you prove herd immunity is a good idea.
(If most of those who have died were in urban areas and travelling on public transport, you'd hope more rural areas would be less affected - but then the period over which people do get infected would just be extended, at least until a vaccine arrives.)
Frankly, I'm not sure either of the maths or the logic, but I think talk of "good news" might feed the optimism of ending restrictions. Now where's Dr Fauci when you need him.
