> Modeling is a helpful tool to try to account for missed cases, such as those that are mild cases potentially missed in current surveillance activities, and the time lag between onset and death. Using an estimated number of total infections, the Infection Fatality Ratio can be calculated. This represents the fraction of all infections (both diagnosed and undiagnosed) that result in death. Based on these available analyses, current IFR estimates range from 0.3% to 1%. Without population-based serologic studies, it is not yet possible to know what proportion of the population has been infected with COVID-19.
https://www.who.int/docs/default-source/coronaviruse/situati...
"Using an estimated number of total infections, the Infection Fatality Ratio can be calculated. This represents the fraction of all infections (both diagnosed and undiagnosed) that result in death. Based on these available analyses, current IFR estimates range from 0.3% to 1%."
And then:
"Without population-based serologic studies, it is not yet possible to know what proportion of the population has been infected with COVID-19."
So even without the population-based antibody (that is what "serologic" means) data, and only using the Chinese data "as of 11 February" available to the WHO the estimate was quite good. The range depends of course also on the age structure of the population -- the countries with much more young people would have closer to the lower number, the others closer to the higher.
1) Edit: the parent post quoted the same segment later too
https://www.bbc.com/news/world-asia-51938035
There have been some doubts regarding the accuracy of later numbers:
https://fortune.com/2020/04/24/china-coronavirus-data-real-l...
https://www.medrxiv.org/content/medrxiv/early/2020/05/18/202...
Other reports were using CFR, which isn't alarmism.
Politically it's also easier to make changes when one highlights the dangers. Not alarmist but certainly manipulative. Fear works and by being alarmed we have saved lives.
> "The current best estimates for the infection fatality risk are between 0.5% and 1%," says Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security.
> That's in contrast with death rates of 5% or more based on calculations that included only people who got sick enough to be diagnosed with tests that detect the presence of virus in a person's body.
> And the revised estimates support an early prediction by Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and a leading member of the White House coronavirus task force. In an editorial published in late March in The New England Journal of Medicine, Fauci and colleagues wrote that the case fatality rate for COVID-19 "may be considerably less than 1%."
Unless “First Thought” simply refers to people who are unfamiliar with how figures such as CFR are calculated. I’ve been seeing the 1% number repeated by scientific figures for months.
Here is a Medium article from a month ago saying the same https://medium.com/@gidmk/what-is-the-infection-fatality-rat...
> From the 13 studies — including 4 models, 4 observational studies, and 5 pre-prints of one kind or another — there was an overall estimate of 0.75% infection-fatality rate, with the 95% confidence interval ranging from 0.49% to 1.01%.