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Covid-19 IFR is *NOT* 0.13% (THREAD)
There& #39;s a lot of confusion and some downright appalling falsehoods in the heated debate about Covid-19. One particular point around which the "let the virus rip" brigade (also known as the morons of Great Barrington) have assembled is the
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There& #39;s a lot of confusion and some downright appalling falsehoods in the heated debate about Covid-19. One particular point around which the "let the virus rip" brigade (also known as the morons of Great Barrington) have assembled is the
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infection fatality rate (IFR) of Covid-19. Unlike the case fatality rate (CFR) which is simply total confirmed deaths over total confirmed cases, the IFR - total *actual* deaths over total *actual* cases - is unobserved.
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Below is a table with some number for the UK - you can see the latest number of deaths (different methodologies) and the corresponding CFRs.
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IFR has to be inferred b/c some cases of Covid-19 go unrecorded, due to insufficient testing & some cases being asymptomatic. On the whole, IFR is lower than CFR for Covid-19 b/c while we have fairly accurate data for deaths, we& #39;ve missed *many* cases (esp. in Mar/Apr)
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IFR then has to be inferred - this can be done by modelling the spread (number of total cases) or by using seroprevalence studies - large-scale testing for antibodies on a representative sample to gauge how many people in the population have had Covid-19.
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The early estimates of IFR in March may have been too high. But some of the "estimates" the anti-lockdown cabal pushes are plainly ridiculous. This applies e.g. to Sunetra Gupta, one of the signatories of GBD who claimed IFR could be "as low as 0.1%"
https://unherd.com/2020/05/oxford-doubles-down-sunetra-gupta-interview/
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https://unherd.com/2020/05/oxford-doubles-down-sunetra-gupta-interview/
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Let& #39;s look at a concrete example. At the Treasury Select Committee hearing two days ago, Gigi Foster, assistant professor of economics at UNSW & "an empirical, data-driven scientist" (these are her words - hold on to them) claimed the IFR is 0.13% based on "WHO data".
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Now let& #39;s look what would that mean for the UK. Below is a table with some *hypothetical* IFR value with Foster& #39;s claim highlighted.
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That& #39;s right - given the confirmed deaths with a positive Covid-19 test in the prior 28 days - i.e. the *most conservative* number - over 34 million people in the UK would have had Covid-19 already. More than a half.
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Why is this nonsense? Two main reasons - firstly, there have been seroprevalence studies done in the UK and they found much lower levels of incidence. The chart below is from the ONS Pilot study - even if we take the upper confidence bounds, still *nowhere near* 50%.
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Link to the study https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/englandandwales4september2020
ICL">https://www.ons.gov.uk/peoplepop... React study finds similar numbers https://www.imperial.ac.uk/news/201893/largest-study-home-coronavirus-antibody-testing/
10/">https://www.imperial.ac.uk/news/2018...
ICL">https://www.ons.gov.uk/peoplepop... React study finds similar numbers https://www.imperial.ac.uk/news/201893/largest-study-home-coronavirus-antibody-testing/
10/">https://www.imperial.ac.uk/news/2018...
The second reason is that we& #39;re still seeing *large* increases in new cases every day (21,242 reported two days ago) - this would not be the case if 50% of the population already have already had covid as we would be nearing the heard immunity threshold.
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The herd immunity threshold for Covid-19 is estimated to be around 60% of the population being not susceptible (acquiring immunity either through developing antibodies after going through covid or through vaccination). See a very simple SEIR model illustration below.
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The daily increases in cases are inconsistent with being close to herd immunity. Thankfully, @t0nyyates called out the BS from the "empirical, data-driven scientist" Foster (incapable of doing basic arithmetic) at the hearing - but these claims are constantly repeated.
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In fact, the countries that have seen the worst epidemics so far are also currently seeing the largest increases - suggesting that herd immunity is far off.
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The IFR is not constant. It depends on many factors such as the population profile of countries, available care, comorbidities and many more. It& #39;s also fallen down over time as we get better at treating covid with dexamethasone, interferon beta or monoclonal antibodies.
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But still, a significant proportion of people who contract Covid-19 sadly die. It& #39;s not a virus that we want to let rip while we "shield the vulnerable" (as though that& #39;s so easy to do - but that& #39;s for a whole another thread).
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The brazen falsehoods that the proponents of these "strategies" often use are despicable and should be called out - especially if they don& #39;t even hold up against back-of-the-fag-packet calculations.
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Below are some proper estimates of IFR & the implied incidence from those estimates in the UK. Note that this illustrates that many cases went undetected & that the March estimates were slightly higher, although as said above, treatment improvement have also lowered IFR since
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In conclusion - be vigilant to outlandish claims and fact-check as much as you can. And listen to the experts in field like @AdamJKucharski @chrischirp @mlipsitch @nataliexdean @K_G_Andersen - not upjumped economist (like yours truly)
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Links to the IFR estimates studies in the last table (top to bottom)
https://www.who.int/bulletin/online_first/BLT.20.265892.pdf
https://www.who.int/bulletin/... href=" https://www.cebm.net/covid-19/estimating-the-infection-fatality-ratio-in-england/
https://www.cebm.net/covid-19/... href=" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7524446/
https://www.ncbi.nlm.nih.gov/pmc/artic... href=" https://gh.bmj.com/content/bmjgh/5/9/e003094.full.pdf
https://gh.bmj.com/content/b... href=" https://www.medrxiv.org/content/10.1101/2020.03.09.20033357v1">https://www.medrxiv.org/content/1... https://www.medrxiv.org/content/10.1101/2020.03.05.20031773v2">https://www.medrxiv.org/content/1...
https://www.who.int/bulletin/online_first/BLT.20.265892.pdf
