Claim: The true infection-to-fatality ratio is definitely about 0.5% to 1%, and most probably around 0.7%, with significant long term morbidity in at least several percent of survivors. Notions that this disease is already widespread or that it has flulike mortality and morbidity or most people are asymptomatic are definitively disproven.
This has been independently estimated in this range before, based on normalizing data from the Diamond Princess and areas where testing was thorough
There are a few robust new pieces of data supporting this now.
1 - Blanket RNA testing in Austria.
Given a 0.3% current acute infection rate and some epidemiological modeling they estimate 1% of their total population has been infected at some point, with a death rate of 0.77%. Maybe a few false negative PCRs, which would lower that number.
2 - Two serology surveys have now happened in Europe. One was in a hard-hit town in Germany, and one was in a hard-hit town in Italy at the epicenter of its outbreak. In both places, they got approximately a 15% seropositive rate. In Germany, we only have information on deaths with positive test results and it comes to 0.35%. In Italy, total excess deaths over this time last year are about 2.5x the confirmed positive deaths and account for 0.1% of the population, giving an infection fatality rate of 0.7%. It is easy to imagine that some deaths did not get positive tests in Germany which along with a less-old population could make up for the difference.
3 - New test data coming out of NYC.
Hardly an unbiased sample, but of 200+ pregnant women coming into a hospital to give birth that were blanket-RNA-tested, 15.3% tested positive.
Of this set of positive tests, only 12% of them were symptomatic on admission, and a further 10% developed symptoms over the course of their 2-day-long stays bringing it to a total of 22% symptomatic upon discharge or transfer. Presumably already-symptomatic very-pregnant women were more likely to be in the hospital already.
Doing a little armchair epidemiology. Let's assume that half of the deaths of currently infected people have happened, due to the lockdown extending the doubling time from three days to more than a week. We get:
~8000 deaths * 2 / (15.3% of 8 million) = 1.3% infection to mortality rate.
If we assume that there were more symptomatic women who didn't show up to normal birthing due to going to the hospital for COVID symptoms, or that there is a good stock of people who have recovered in the city, we get a lower death rate. If 20% of the total population was ever infected, we get a 1% mortality rate. 30% ever infected, 0.67%.
EDIT: 4 - Apparently there is a similar maternity ward study in Stockholm, revealing 7% positive. There have been 550 deaths there, and a population of 2.3 million. If we again assume half of current cases that will die has died, we get a infection to fatality ratio of 0.68% without further corrections. I suspect they haven't crushed the doubling time as much as NYC, raising this number, which then can get lowered down again as I did above.
EDIT: 5, a meta analysis of a whole bunch of research comes to exactly my original conclusion, 0.5% to 1% with a central tendency of 0.8%.