More infected means lower death ratio, yes?
It means a lower IFR, or EIFR (Estimated Infections Fatality Rate) if you will, but the daily numbers of serious, critical, and fatal cases are unchanged. They are what they are. Presently, US daily fatalities are around 2k and not showing any real signs of diminishing soon.
As chaotic as it is in Brazil right now we don’t know the true death toll either. No way to know what the CFR really is.
That true as far as it goes.
But at no time in all of recorded history were the people who could only be proved to be infected by sophisticated laboratory procedures counted in the denominator.
For every epidemic EVER only people ill enough to seek medical care were counted as cases.
EVER!
If you want to feeeeel good about this pandemic, add as many people as you like to the denominator. Why stop at those who are sick? Why not add everyone who tests as exposed even if they never get sick? Why stop there? Why not put the population of the whole country in the denominator? After all, they might have been exposes! Hey! How about the entire population of the planet, don't they deserve to be counted???
That'll make the death ratio really low!
And really false, when compared to every disease that has ever swept through a population in the past, when those ignorant, benighted people only counted the overtly sick in their reckoning of how many died of the disease...
Only if the infected are tested positive. If you just assume a certain percentage of the population has been infected, you are talking an entirely different metric.
“More infected means lower death ratio, yes?”
If you assume that all have passed the threshold to active status and then resolved. Who knows how they are counting? But guaranteed most of those cases have not yet resolved, and if Brazil’s HCS collapses, you get a huge spike in deaths, both direct and indirect. But in general, more infected means more dead in direct proportion. Again, there is no vast hidden herd of already infected that somehow survived and gained immunity without being detected.
In a situation where the testing and HCS are saturated - like Brazil - you can ballpark the case count by assuming that only the serious and critical cases are being officially reported and that there are another 4x mild and asymptomatic, and then if there is community spread (usually these things go together) another 3 cohorts (based on R0 of virus) of the same size incubating. Altogether you get 20x the reported cases as your upper limit for infected - with a lot, 75%, of the cases TBD as far as severity goes.
That’s in a saturated situation. If testing is keeping up or catching up and you have contact tracing going on, and people practice aggressive social distancing, that reduces the multiplier, possibly by a large amount. But overall, 2% or more of the cases will be fatal. Barring a miracle cure.