More about NY’s antibody test results…

So what about the 14% who tested positive for antibodies?

Let’s start by flashing back to what we said before the test results came in:

Estimates from other earlier-infected countries indicate that only 15% of people infected by the coronavirus experience severe symptoms.

So, given that NY has had about 250,000 confirmed cases (which required severe symptoms), we would expect that the total number of people already infected in New York is 1.67 million (250,000 confirmed cases divided by 15%) … which is 8.6% of the NY population (1.67 divided by 19.5).

OK, the first wave of testing found that 14% of sampled New Yorkers tested positive for coronavirus antibodies … indicating that they had been infected.

That projects up to about 2.7 million people (14% times 19.4 million population).

For details, see: NY antibody test results

So, is 14% testing positive for antibodies good news or bad news?


Answer: it depends.

14% testing positive is a higher number than we would expect based on other countries’ relationship of confirmed cases to total cases (the logic above).

That’s bad news in that it might indicate “leakage” from the “cone of protection” allegedly provided by the stay-at-home mitigation plan.

Note: Some leakage is to be expected since, according to Gallupp, approximately 60% are still working outside-the-home and most home’s cone-of-protection is breached when residents go to work or run essential errands (e.g. trips to the grocery store).

But, based on these test results,  90% of New Yorkers who have gotten infected by C-19 have had no or mild symptoms. That’s very good news!

And, it’s good news because the increment over what might be expected is composed of asymptomatics who aren’t materially affected directly by the virus … and the increment implies a lower coronavirus death rate since the denominator of cases is increased.

A along those factors, on balance, I’d score the 14% as good news.


Somewhat more equivocal: If 14% have been infected (and are potentially immunized from relapses) … that means that 86% of the population is still vulnerable to getting infected … and some portion of them are terminally vulnerable.

That’s important because “flattening the curve” didn’t necessarily “save” lives … it contained the immediate surge in infections to levels that the health care system could handle … but, by definition, pushed many (most?) potential infections into the future.

For sure, the 14% level of people already infected is way below the 60% to 80% level needed for “herd immunity”. That’s too bad.

It would be nice if the virus died a natural death when summer arrives. While recent reports of heat & humidity depressing the virus are promising, we can’t count on that.

So, we’re still highly dependent on social distancing and masks … and, on the rapid development of drug therapies that ease the virus’ effects … and vaccines that stop the virus in its tracks

Related posts:

NY antibody test results

NY’s missed testing opportunity

Squeezing the NY antibody test results

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