The disease-induced herd immunity level for Covid-19 is lower than the classical

Re:The disease-induced herd immunity level for Covid-19 is l... by lostlogin on Saturday May 09, 2020 @02:20PM (#23127126)

> The classical herd immunity level hC is defined as hC=1−1/R0

How do you use this in places where transmission is less than 1? New Zealand now has a transmission rate considerably under 1, but this seems to break the calculation.

Does this mean that a reproduction number under 1 doesn’t need herd immunity? We do, because we can’t stay locked down indefinitely, and presumably our rate will go up when we relax restrictions.

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Re:The disease-induced herd immunity level for Covid-19 is l... by Izkata on Saturday May 09, 2020 @02:30PM (#23127213)

If reproduction rate stays under 1, it will eventually completely die out on its own.

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Re:The disease-induced herd immunity level for Covid-19 is l... by jaynetics on Saturday May 09, 2020 @02:22PM (#23127148)

R0 is the reproduction rate without any countermeasures.

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Re:The disease-induced herd immunity level for Covid-19 is l... by lostlogin on Saturday May 09, 2020 @02:42PM (#23127304)

Thanks, this is the key.

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Re:The disease-induced herd immunity level for Covid-19 is l... by SpicyLemonZest on Saturday May 09, 2020 @02:30PM (#23127215)

In this kind of modeling, outbreaks are considered to be impossible once transmission is driven below 1. (The herd immunity level is just the level at which the transmission rate is driven below 1 without additional interventions.)

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