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Comment by rocha | Hacker News Reader

My understanding is that the current estimated IFR from those studies (NY specially) is between 0.6% and 1.2%. I think flu is around 0.1% (however I am not sure if that is the CFR or the IFR). The second factor to consider is the attack rate, how many people are likely to get infected. For flu is around between 10% to 15% of the total population, while for Covid it is, potentially, larger than 80% (no natural immunity and no vaccines). It is however unlikely that it will reach that level given the current containment and mitigation measures. But if it reaches something like 40% (double of the latest NY estimate), it will mean covid is between 16 to 48 times deadlier than the flu.

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I believe 0.1% is the CFR for the flu, and the IFR is close to 0.04%?

Thanks. I have seen serious estimates of 0.1% CFR for the 1957 and 1964 flu pandemics, but only notes saying that the seasonal flu CFR is <0.1%. Do you have a source for the 0.04% IFR?

No (hence the question mark), I'm seeing 0.04% pop up everywhere but I haven't found the source for the number.

But it seems plausible if the CFR is <0.1% as there are both asymptomatic cases of the flu and people don't always go to the doctor even if they have symptoms. It seems like caring about IFR was rare before this pandemic and the lockdown

Got it. Thanks. I think it may be because the IFR is less reliable, since for most diseases it requires a gross estimation the real number of infected persons. It is probably more popular these days because people are putting a lot of effort into the comparisons with the seasonal flu.

IFR for flu is less than 0.1% according to the CDC.

https://www.cdc.gov/flu/about/burden/index.html

That's not the IFR since they're not counting asymptomatic cases (based on a quick read)

They don't mention IFR anywhere as far as I can see

Yes, sorry, I thought we were comparing IFR and not CFR.

No worries, I had made the same mistake. I just wanted to point out that the attack rate is also part of the fatality equation, and it is commonly not taken into account.

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