Many COVID-19 contrarians, including those behind the Great Barrington Declaration, *still* cite John Ioannidis' inaccurate estimate of SARS-CoV-2's fatality rate.
So let's go over how atrocious Ioannidis' paper is.
Ioannidis uses antibody (a.k.a. seroprevalence) studies to estimate the number of people infected with the virus SARS-CoV-2. He then calculates IFR by dividing the number of COVID-19 deaths by the number of infected people.
Beware when folks cherry-pick Ioannidis' outlier of ~0.23% as if its credible.
Public Health Agency of Sweden:
"Globally, it is estimated that 0.5–1 percent of those who are infected with COVID-19 die" web.archive.org/web/2020103000…
Also beware of people who try to mislead you into thinking the World Health Organization agrees with Ioanndis' low IFR estimate, or with his claims that SARS-CoV-2 has an IFR similar to that of seasonal influenza.
Antibody studies can use a *representative* sample of the population to accurately estimate the number of infections. Otherwise, one could over-estimate the number of infections + under-estimate IFR.
Scientists know how to get representative samples.
Ioannidis mostly cites studies that use non-representative sampling. That causes him to over-estimate seroprevalence + thus under-estimate IFR.
Studies with non-representative sampling may be useful for other purposes, but not for estimating population-wide IFR.
12/
For instance, blood donor studies:
- under-sample older people, a population more likely to die of COVID-19
- include people who go outside to donate blood, + are thus more likely to interact with people and get infected
Volunteers who hear antibody testing is occurring, but were not targeted for testing by random selection, may ask to be tested because they think they're infected (ex: they have symptoms, known prior exposure to an infected person, etc.).
People in schools, workplaces, shoppers, etc. are not necessarily representative of the general population. For instance, they're socially interacting in a closed setting, increasing their risk of infection.
Re: "It's telling that Ioannidis tried to infer an IFR of 0.00% from that."
Ioannidis states it's risky to draw inferences from a sample size of less than 500... but doesn't let that stop him from using ~365 infections to infer a low IFR.
Paper 37 (Karachi, Pakistan) should also be dropped, because Ioannidis uses an unsound method of getting the COVID-19 deaths he applies in his IFR calculation.
(note: part 21/ should read say "only 22", not "only 23")
That's barely a quarter of the 61 studies Ioannidis said supported his IFR estimate. But at least the studies are now of better quality.
27/
Yet problems remain.
Take the example of paper 3 (for Brazil). Months ago when I first saw what Ioannidis did with paper 3, I lost any remaining confidence I had in the credibility of his paper and in his IFR work in general
To avoid paper 3's larger stated IFR, Ioannidis invented a new calculation based on his misinterpretation of figure 3 from the paper. In doing so, he contradicted paper 3 and used reasoning that makes no sense.
There are other IFR calculation issues. For example, Ioannidis gives an uncorrected IFR of 0.45% for paper 43 for Geneva (see image on the right side in part 8/).
- over-estimating seroprevalence for papers 21, 28, 49 (Gangelt, Guilan, Los Angeles), and papers 56 + 57 under-estimating seroprevalence by a smaller proportion
- Ioannidis predominately uses studies with non-representative sampling
- excluding the most non-representative studies doubles his IFR to ~0.5%
- correcting his other mistakes would most likely increase his stated IFR even more
"Ioannidis told viewers that the virus has an “infection fatality rate that is in the same ballpark as seasonal influenza.”" buzzfeednews.com/article/stepha…
Alongside parts 5/ and 6/:
"[IFR in a typical low-income country:] 0.23% (0.14-0.42 [...]) [...].
[In a typical high income country:] 1.15% (0.78-1.79 [...])" web.archive.org/web/2020110103…
Ioannidis uses PCR results for paper 56, even though PCR-positive antibody-test-negative people would be less likely to die in time to be included in his IFR.
That allows him to reduce paper's 56's IFR from 1.67% to 0.91%.
And Ioannidis reports a 1.16% IFR for paper 45 from part 8/ (for England, without excluding nursing home deaths), while the source he cites gives an IFR of 1.43%.
The population fatality rate, or PFR (i.e. COVID-19 deaths per capita), should be less than IFR, since you can't have more people infected than actually exist.
Yet in at least 3 instances, Ioannidis gives 'corrected' IFRs that are less than PFR.
@luckytran In which Bhattacharya does the intellectual equivalent of claiming vaccine denialists are being unfairly persecuted because Andrew Wakefield's blog told him so
"What they're doing is focused protection, and you can see the result. The infection rates are going up in Sweden, but the death rates are not." edhub.ama-assn.org/jn-learning/vi…