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Comment by greedo | Hacker News Reader

Simple math. Herd immunity requiring 50%. World population 7.6B. So 3.8B infections. Hospitalization rate is roughly 10%, so 380M hospitalizations. IFR is roughly 1%, so 38M fatalities.

So again, 3.8B infections, 380M hospitalizations, and 38M fatalities. Even assuming a magnitude of error, we're still looking at 38M hospitalizations and 3.8M deaths.

Michael Osterholm had a really good analogy into COVID. We're wrong to thing of it in waves; it's more like wildfire. Where it finds fuel, it will burn until the fuel is gone.

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It's a little more complex than that. The herd immunity threshold estimates have assumed that everyone is equally susceptible. However the reality appears to be that some people have at least partial immunity, perhaps based on genetics or prior exposure to similar viruses. This is an active area of research, and for now the level and extent of population immunity remains an unknown variable.

The best estimate from the CDC indicates an IFR of 0.65% in the US. That's a major difference from 1%.

https://www.cdc.gov/coronavirus/2019-ncov/hcp/planning-scena...

A recent sero-prevalance study in Mumbai found that 57% of people in the slums had antibodies, which would put those areas close to the theoretical herd immunity threshold. Despite limited access to advanced healthcare there the IFR was under 0.10%, although it's possible that some deaths weren't accurately recorded.

https://www.cnbctv18.com/healthcare/57-sero-prevalence-in-sl...

A change from an IFR of 1% to 0.65% would still mean 25M fatalities. And that's a CDC IFR from a country with vast, vast resources. As this circles the globe looking for firewood, it's going to burn a long time.

I'm extremely skeptical of the link you provided. Small sample size and there's no other supported data to indicate an IFR in line with influenza.

No, herd immunity requires >90, if not >95℅. and that assumes that herd immunity is even possible - there are plenty of indications that the covid-19 cured don't have long-term immunity. That leaves only either eradication, which the US, Brazil and Russia ruined for all of us, or that it ends as part of the annual flu family.

I was trying to be generous with the 50%. I believe it will be around 65% when all is said and done.

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