Actually, Dr. Ioannidis article estimated the IFR for SARS-CoV2 at 0.15% is based on the world's population. Because the US population is older and has far more people with illnesses that increase the risk of death if infected with SARS it is likely the IFR is higher than that seen in most other countries. I believe, Dr. Ioannidis's study [the first to use sereological testing to estimate the number of people who had been infected with SARS-CoV2] of people living in Santa Clara originally estimated the IFR at 0.17%, but based on some valid criticism of their methodology ended up being closer to 0.25%. Keep in mind that we were looking at the IFR back in March and early April of 2020 when no one was vaccinated, MDs had few effective strategies and no proven drugs to treat very sick people back then. So the IFR (the risk of dying if infected) is no doubt much lower today than it was back in early 2020.
Now the study by Meyerowitz-Katz was also looking at the IFR back before there was many viable options to prevent and treat SARS-CoV2 infections. His estimated IFR was 0.68% back then. In hindsight Dr. Ioannidis may have under estimated the IFR and Meyerowitz-Katz may have overestimated it. Hindsight is better than foresight and the IFR today is almost certainly been cut by at least 2-3-fold thanks to vaccinations, monoclonal antibodies, medical use of corticosteroids, anti-clotting drugs, proning the patient, etc.. Keep in mind that most Americans have had the flu and/or multiple flu shots and we have Tamiflu and other treatments MDs have long been familiar with that make the IFR far lower. Now that is also the case for SARS-CoV2 so my estimate that its IFR is likely now similar to that of a typical flu is likely reasonable. Of course, with the much higher R0 a far greater number of Americans have been infected with SARS-CoV2 than with the flu so even with a similar IFR we still have seen far more people infected and so that leads to more deaths even though the odds of dying if infected (IFR) are similar. Indeed, so many Americans have been infected and/or vaccinated now against the Wuhan virus that I suspect 2022 will see far fewer deaths with COVID-19.