From what I’m reading fatality rates of all new diseases or outbreaks tend to fall as more and more are tested. Rona won’t be different. I have also read some skepticism over these serological tests. For one there are faulty or untested kits from China used to carry them out. They may be unreliable.
Then you have some conditional probability and Baye’s theorem involved. There are two figures relevant for each test; sensitivity-probability of returning positive for positive guys and specificity-probability of returning negative for negative guys. Both Sensitivity and specificity are less than 100%. Bottom line is, if you projected the sample onto the population you’d have unacceptable levels of false positives and false negatives, as high as 80%. Cure for this is very high quality tests whose specificity and sensitivity approach 100%.
Then there is the question of whether there was sampling bias.
That’s why sly Cuomo was hesitant to comment on the results yet he shared them. It’s exciting but he will be the last to run with them as it were lest he is wrong,and costs of such blunders are human lives and perhaps his presidential ambitions.
I think there is is more need for these tests, more refining so it’s too early to celebrate.