US Covid19 Cases Underestimated 80-Fold?

Penn State University reports:

... the number of early COVID-19 cases in the U.S. may have been more than 80 times greater and doubled nearly twice as fast as originally believed. In a paper published today (June 22) in the journal Science Translational Medicine, researchers estimated the detection rate of symptomatic COVID-19 cases using the Centers for Disease Control and Prevention’s influenza-like illnesses (ILI) surveillance data over a three week period in March 2020. “We analyzed each state’s ILI cases to estimate the number that could not be attributed to influenza and were in excess of seasonal baseline levels,” said Justin Silverman, assistant professor in Penn State’s College of Information Sciences and Technology and Department of Medicine. “When you subtract these out, you’re left with what we're calling excess ILI – cases that can't be explained by either influenza or the typical seasonal variation of respiratory pathogens.” The researchers found that the excess ILI showed a nearly perfect correlation with the spread of COVID-19 around the country. Said Silverman, “This suggests that ILI data is capturing COVID cases, and there appears to be a much greater undiagnosed population than originally thought.” Remarkably, the size of the observed surge of excess ILI corresponds to more than 8.7 million new cases during the last three weeks of March, compared to the roughly 100,000 cases that were officially reported during the same time period.

The report continues:

...the researchers’ model suggested that [in New York] at least 9% of the state’s entire population was infected by the end of March. After the state conducted antibody testing on 3,000 residents, they found a 13.9% infection rate, or 2.7 million New Yorkers.

The authors of the study, which was published in the journal Science Translational Medicine conclude that:

...“Our results suggest that the overwhelming effects of COVID-19 may have less to do with the virus’ lethality and more to do with how quickly it was able to spread through communities initially... A lower fatality rate coupled with a higher prevalence of disease and rapid growth of regional epidemics provides an alternative explanation to the large number of deaths and overcrowding of hospitals we have seen in certain areas of the world.”

      Related     
ZH: "This Is Not Just Accidental": How One Coronavirus Mutation Helped The Virus Conquer The Globe
YDN: Long periods of lockdown could weaken the immune system and leave people more vulnerable to dangerous viruses, Oxford epidemiologist warns
YDN: Coronavirus genome found in Spain wastewater samples from March 2019, scientists reveal
ZH: Coronavirus Causes Weaponized 'Tentacles' To Sprout From Infected Cells, Directly Inject Virus Into New Ones
ZH: "Disturbing Parallel To HIV": COVID-19 Can Cause Depletion Of Important Immune Cells, NY Times Admits

Has New York City Achieved Covid19 Herd Immunity?

New York State Governor, Andrew Cuomo announced today that random surveys indicatd that 14% of New York State residents now have antibodies to Covid19, and in New York City, the number is 21%.

Assuming that being antibody positive means Covid19 immunity, that is immunity from re-infection, has New York achieved so-called herd immunity, which is to say immunity to the Covid19 virus that is sufficiently widespread to prevent each newly infected individual from, on average, passing the virus to more than one other person?

If herd immunity has been achieved, then the decline in reported deaths should continue even if the present measures of quarantine and lock-down are abandoned.

Unfortunately, there is no clear guide as to the infection frequency required for herd immunity. Assuming a reproduction number of more than three, which is to say the average number of people each infected person infects before the development of any population immunity, then an infection rate of over 60% of thereabouts would be needed to end the epidemic, assuming that people interact and spread the disease in a random fashion. However, people do not interact in a random fashion. Some are much more effective as disease spreaders than others. Children, for example, are excellent spreaders, both among themselves and among family members and family friends. Old folks, however, tend to live relatively isolated lives and are therefore extremely poor spreaders. It is not implausible, therefore, to suppose that an immunity rate of 21, as in New York City, or even as low as 14% for New York State as a whole, is sufficient to cause the epidemic to die.

As the various jurisdictions dealing with the epidemic make decision on ending lock-downs and other quarantine measures, and as more surveys of population immunity are reported, we will soon know.

Related:
YDN: R nought in New York City is less than one: Herd immunity achieved
The Hill: The results are in — stop the panic and end the total isolation
The Irish Savant: Heads I win, tails you lose
DC Whispers: Sweden Kept Economy Open, Yet Has A Mortality Rate Similar To America’s
Pepe Escobar: What Did U.S. Intel Really Know About the ‘Chinese’ Virus?
Post News: 94% of All NYC Coronavirus Patients Have Underlying Health Problems