In other words, this means "we can all agree this is" NOT necessarily "more serious than the flu" and most other infections now. Thank you for noticing.
If the CDC actually thinks that 75 percent of NYC has already been infected then it doesn't jive. However I doubt they believe that.
Notwithstanding the CDC, the likely infection rate of NYC is closer to 19 percent, which would mean they are approaching herd immunity on the upper end (its a range between 7 and 27 percent).
In the meantime, of equal interest is Worldometers whose recent analysis speaks to NYC in particular. They have used the data provided by New York City, the New York State antibody study, and the excess deaths analysis by the CDC to derive the most accurate estimate to date on the mortality rate for COVID-19.
In sum, their findings are:
Actual cases of COVID-19 is 1.7 million, which is 10 times the number of confirmed cases. The NYC antibody testing study of May 1st showed 19.9% of population had CV-19 antibodies in a population of 8.4 million. The number of confirmed cases reported as of May 1 by New York City was 166,883 , more than 10 times less.
Actual Deaths from CV-19 is 23,000, almost twice the number of confirmed deaths. As of May 1, New York City reported 13,156 confirmed deaths and 5,126 probable deaths (deaths with COVID-19 on the death certificate but no laboratory test performed), for a total of 18,282 deaths [source]. On May 11th the CDC calculated 5,293 more "excess" deaths. After adjusting for May 1, WoM got 5,148 additional deaths, for a total of actual deaths of 13,156 confirmed + 5,126 probable + 5,148 additional excess deaths calculated by CDC which equals 23,430 actual COVID-19 deaths as of May 1, 2020 in New York City.
Some additional nuggets they provided:
Infection Fatality Rate (23k / 1.7M = 1.4% IFR). As of May 1, 1.4% of those infected have had a fatal outcome, while 98.6% recovered.
Mortality Rate for the NYC general population is (23k / 8.4M) which is 0.28%.
Mortality Rate for those over 65 NYC population is (17,242/1,184,223) which is 1.46% (Calculated by post author).
Mortality Rate for those under 65, with and without underlying conditions is .09% (see below).
Out of 15,230 confirmed deaths in New York City up to May 12, only 690 (4.5% of all deaths) occurred in patients under the age of 65 who did not have an underlying medical condition (or for which it is unknown whether they had or did not have an underlying condition). (And remember 85 percent of the NYC population is under 65).
So as of May 1 there was 6,188 deaths under the age of 65, with and without underlying conditions: 6188 / 7,214,525 (total population under 65) = 0.09% CMR. And at least 89% of the times, the person who died had one or more underlying medical conditions.
Takeaways: in NYC, the worst and most intense outbreak in the country (the city with the highest density), those NYC citizens over 65 were 16.222 times more likely catch and die from CV than those under 65 (which are 86 percent of the population). And of those 6,188 under 65 deaths only 690 were absent comorbidities.
In short, the chances of an under 65 healthy New Yorker, without comorbidities, dyeing from COVID is .009% which is effectively zero.
Whatever the implication of the CDC, CV-19 is not a substantive threat to those under 65 without comorbidities.