20%. Yay? How much longer until herd immunity?
The word you are looking for is endemic, i.e. never goes away and cannot be effectively eradicated.
Congratulations on adding another biological landmine to modern existence.
1) 3.4% of people who catch it die every year, and life changes
2) It mutates, and gets worse. Unlikely, but not impossible. Or it leads to long-term disability which we don't know about yet (not unlikely). Etc.
3) Kids get it early, acquire partial immunity as it passes, and it becomes another variant of the common cold/flu.
Most of the time, #3 is the outcome. It's worth taking seriously because #1 and #2 will eventually happen if we ignore these, but....
Why do you think the IFR will increase by a factor of almost 7?
I'm now seeing WHO is estimating 0.5-1.0%, which is possible too.
I don't think we'll know for some time. One of the problems is people who have yet to die... You can't get a good estimate until long after a pandemic, to catch all the stragglers.
I believe Massachusetts comes as close to capturing 100% of infections as anyone at this point, although that wasn't always the case. There is a lot of test infrastructure.
CFR can overestimate or underestimate IFR. In most past pandemics, CFR significantly UNDERestimated IFR during the pandemic, because the raw numbers include a lot of people who are sick, but haven't died YET.
There is a tendency to take CFR, apply very liberal corrections, sometimes multiple times, and get artificially low IFR numbers. Those aren't really plausible, even looking at scenarios where we could catalog all cases (e.g. the cruises had an IFR just over 2%, with state-of-the-art medical).
My general impression, looking at data, is that the IFR was around 3-ish percent early on, and got better, potentially due to mutations making the virus less fatal, lower initial viral loads due to precautions, and/or better treatment.
So it does not capture 100%.
> CFR can overestimate or underestimate IFR.
Incorrect. CFR cannot be higher than IFR. The number of deaths per confirmed infection obviously isn't higher than the number of deaths per infection (confirmed or unconfirmed).
I'll continue to believe epidemiologists who actually have a clue what they are doing over your "general impression".
If you want, an exert from an epidemiology text:
"A CFR can only be considered final when all the cases have been resolved (either died or recovered). The preliminary CFR, for example, during an outbreak with a high daily increase and long resolution time would be substantially lower than the final CFR."
The cited numbers are preliminary CFR, not final CFR. The key question is final IFR. Final IFR can be lower or higher than preliminary CFR.
I'm done here.
I would be cautious about estimating countries that are only now having their first major outbreak (for example Czechia) for exactly the reason that you cite, but not every country is in that state.
Put another way, we are no longer living with preliminary data in much of the world.
* Last death of Diamond Princess occurred after more than 2 months.
* Over the past two months, the number of known cases in the US roughly doubled from 8 million to 16 million.
This means there are a lot of people who haven't died yet, and dividing deaths by cases is an underestimate of CFR by up to a factor of 2.
That doesn't mean we don't have the data. We could e.g. take the infections from June and look at how many of those resulted in death as a final CFR estimate. However, the number I gave (deaths over cases) didn't do that. It's a preliminary CFR without that sort of correction, and a correction to final IFR can go up (people who haven't died yet) or down (unidentified cases).
anoncake argued this was an overestimate by definition, and anyone who said otherwise didn't have a clue. anoncake was wrong.
Dead people / Recovered people and that is around 3 percent, down from 5 to 7 percent a few months ago.
Infections / deaths is not accurate as cases in progress are added to those with definitive outcomes.
That can also be seen as a best case, given nobody currently infected does not die.
A worst case can be seen assuming everyone infected will die.
But if we want to know the percentage of people who get sick and die, we have to compute that percentage with the people who got sick and did not die and their case ran its course to a definitive outcome.
Infections lead to outcomes.
Outcomes are where the dead vs not dead become known.
Everyone infected will eventually arrive at an outcome.
Divide dead people by recovered people to assess true risk of death from COVID.
Dividing dead people by infected people represents a best case, overly optimistic risk due to the fact that cases that ran their full course to a definitive outcome are mixed together with cases in progress. Doing that biases the risk perception down below actual risk and can be dangerous.
I know one person who died, who did not have to, and they died because they made choices after having evaluated risk incorrectly.
They have their reasons for that metric. That too doesn't make (dead/recovered) wrong.
There are dead people in my life, with whom I had this discussion. "Calculated risk" = optimistic.
The IFR combines futures with actual and does not represent an outcome based risk assessment.
Nature however, will definitely take you, or any of us, to an outcome, should we become infected.
In my (admittedly naive) thinking, if R0 was 2, say, then if 50% of the people got it (and were therefore not able to get it again, and therefore not able to spread it), then the effective R0 would be 1.
Isn't the R0 for "no restrictions" something like 15? So I'd guess we'd need 93%? But I also have seen figures from 50 to 95% quoted for herd immunity so who knows?
Anyone with real numbers, feel free to supply them...