Interesting method from @GidMK and co-authors for calculating IFR from PCR-based cases.
(IFR is the proportion of SARS-CoV-2-infected people who die COVID-19;
PCR measures viral genetic material in people;
Cases are people who were infected)
The basic idea is that some countries had relatively few infected, and tested with PCR so thoroughly, that their PCR testing got a relatively large proportion of infected people.
Their method yields a range of IFR values consistent with those from serology [i.e. antibody testing], which provides independent validation for their method.
green: their PCR-based methods
blue: Serology-based estimates
Their South Korea IFR: ~0.8%
Serology study: ~0.8%
(assuming the 1 positive result out of 1440 is not a false positive; ~36,000 infections, ~300 deaths 4 weeks after study mid-point)
There are other PCR-based methods for estimating IFR. Below is an example for Stockholm, Sweden (@GidMK's method wouldn't work there, since they didn't catch a large enough proportion of their cases).
Their serology-based method and PCR-based methods also fits with PCR-based IFR results from the Diamond Princess (a cruise ship on which many people were infected with SARS-CoV-2, with 14 dying of COVID-19).
Thread on a myth Jay Bhattacharya (@DrJBhattacharya) continues to peddle to undermine confidence in public health agencies and to suit his policy agenda.
The myth may undermine responses to future public health emergencies.
Reporting systems are not perfect, so they sometimes miss infected people. That makes reported cases less than total infections, and thus CFR is higher than IFR.
The WHO was open about this since the early stages of the pandemic: