Given controversy and confusion over aspects of COVID-19, particularly over comparisons and contrasts with the mortality risk of seasonal flu, this question seeks data and findings on the mortality risk (Infection Fatality Rate) of Covid-19.
The mortality risk, or Infection fatality rate (IFR), sometimes known as ‘mortality rate’, ‘death rate’, or 'lethality' represents the risk of dying after contracting the virus, and is calculated as the number of deaths divided by the number infections.
The mortality risk (IFR) of COVID-19 is often overlooked in mainstream news media, which tends to focus on the case fatality rate (number of deaths divided by the number of CASES), or falsely equate/conflate the two.
The case fatality rate is in itself not a valid indicator of the mortality risk of a virus as it does not account for unreported/asymptomatic cases and therefore the true number of infections, or estimates of them. Hence the interest in data/studies on the mortality risk.
Source / information criteria:
For the purposes of this question, all answers must come with specific, referenced data/findings based on (or at least explicitly indicating) the number of infections (either directly known through testing of the entire study population, as in confinement/isolation situations, or based on modeled/estimated/extrapolated number of infections), and the number of deaths in each case.
This question does not seek answers containing personal estimates from respondents, and sources providing guesses based on anecdotal evidence or impressions/experience do not meet the criteria for this question.
Information based entirely on the CASE fatality ratio (i.e which ignores the number of unreported infections/asymptomatic infections) is not of interest for the purposes of this question for the reasons mentioned.
To avoid statistical errors due to small sample sizes, please limit sources to only those findings which are based on populations/sample sizes (total number of infections, either estimated or known) greater than 500.
Other coronavirus strains already circulating among population before COVID-19 (eg. 229E, HKU1, NL63, OC43) are not of interest for the purposes of this question.
In the case of news articles, obviously references should be included in support of data/findings, or at least traceable from the article, otherwise the information is not useful.
Goes without saying that the ratio/risk presented in any given source does not, in itself, determine the quality of the answer, and all answers meeting the given criteria are encouraged, regardless how consistent or inconsistent the findings they contain may be with other findings.
Feel free to indicate the following data points if they are known when indicating any sources of information, as they are of obvious relevance for the mortality risk (IFR). In any case, I will read all posts and summarize the data under various headings as I have done in my own answer to the question, which I will update as answers come in.
- Average age of the people considered in the study, and age stratified mortality risk (mortality risk for different age groups) if known.
- How much time has passed since all persons considered in the study became infected if known, as deaths can occur after data is collected.
- Whether Outcome delay adjustments (adding a percentage increase of deaths due to possible deaths after releasing data) are included in the information, if known.
- Possible underlying illnesses which can increase likelihood of death if known.
- Other factors.
Below I have provided an answer (now a wiki) where all the sources which I have found or have been provided here meeting the given criteria are summarized with the corresponding mortality risk.
Edit (in light of one answer below):
Please note, answers based on 'common sense', or which cite or are based on data pertaining to cases (rather than infections) do not meet the criteria for this question. For the sake of the clarity and relevance of the data found here, please take the necessary time to research and understand these terms and the criteria specified for the data provided here before posting any data / papers.