Study: 50 to 85 Times as Many People May Have Been Exposed to Coronavirus Than Who Have Tested Positive for It, Indicating That the Chinese Flu is Far Less Deadly Than Models Suggest
Plus: Covid Briefing

Interesting.

This researchers sought volunteers in Santa Clara County, California, to test their blood for antibodies to coronavirus.

Under the three scenarios for test performance characteristics, the population prevalence of COVID-19 in Santa Clara ranged from 2.49% (95CI 1.80-3.17%) to 4.16% (2.58-5.70%).

These prevalence estimates represent a range between 48,000 and 81,000 people infected in Santa Clara County by early April, 50-85-fold more than the number of confirmed cases.

Conclusions

The population prevalence of SARS-CoV-2 antibodies in Santa Clara County implies that the infection is much more widespread than indicated by the number of confirmed cases. Population prevalence estimates can now be used to calibrate epidemic and mortality projections.

Something to keep in mind: They sampled the population for antibodies, like pollsters sample a population for their voting preferences. Sometimes polls are way out of line with reality. Sometimes samples are skewed.

Also: The thread below suggests that the true coronavirus fatality rate is less than that of the common flu.

Justin Hart concludes this by taking the number of fatalities and dividing by the true infection rate of coronavirus. Not the reported rate. The true rate, which includes both those who get tested and who thus are included in medical reports, as well as the many people who never get tested and thus are invisible to the medical reports.

But he's assuming the common flu death rate is found through the same method -- divide fatalities by the True infection rate (Reported + Invisible Non-reporteds which must be estimated by statistical sampling).

But is that true? Or is the influenza fatality rate only fatalities divided by reported cases only?

This is a little mathy, but if the common flu fatality rate is determined not with all cases (reported and estimated nonreported) in the denominator, but instead just the reported cases, that would mean that the flu's fatality rate would also plunge if you started including all the many, many nonreported flu cases in your estimates of how deadly it is.

Personally, I've had what I'm 99% sure was the flu like six times, but I only saw a doctor for it once. I imagine lots of people have the flu but don't bother with a doctor unless it gets really bad or persists for an obnoxiously long time. (As mine did when I finally saw a doctor.)

So, you know, if the flu's deadliness is usually based on reported cases only, if you added in an estimate of nonreported cases, its fatality rate could fall from 0.1 to 0.01 -- meaning, covid would still be ten times as deadly.

I'm not sure about that last bit, about how the common flu fatality rate is calculated.

The daily coronavirus briefing has started:

posted by Ace at 06:24 PM

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