Thread by @GosiaGasperoPhD

The meaning of R

Sustained R, starting from 1,600 daily new cases (dnc):

R=0.97 ➡️ halving time (ht)=3 months ➡️ 1,020 dnc in 2 months
R=0.8 ➡️ ht=12.4 days ➡️ 60 dnc in 2 months, zero in 4.5 months
R=0.6 ➡️ ht=5.4 days ➡️ ZERO dnc in *2 months*

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The meaning of R

Sustained R, starting from 1,600 daily new cases,

Toll of the first 2 months:

R=0.97 ➡️ 76,300 cases ➡️ 1,220 deaths
R=0.8 ➡️ 28,400 cases ➡️ 450 deaths
R=0.6 ➡️ 13,300 cases ➡️ 210 deaths

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Toll of subsequent months (after the first 2 months):

R=0.97 : a lot of cases & deaths, high risk of exponential surge & next lockdown
R=0.8 : some cases and deaths, high risk of exponential surge & next lockdown
R=0.6 : NOTHING

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What gives which R value

R=0.97 ⬅️ some restrictions
R=0.8 ⬅️ demi-lockdown (e.g. businesses closed but schools open, insufficient travel restrictions, etc.)
R=0.5-0.65 ⬅️ regular lockdown (e.g. 1st wave Austria, New Zealand, 2nd wave Melbourne/Victoria Stage 4/3)

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For reference, Alberta's halving time in the 1st wave was 7.8 days (an equivalent of R=0.7 )

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Extra ingredients:
✅ Addressing aerosol transmission of COVID-19
✅ Vaccine
will additionally lower the R

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Thank you @Imgrund for answering my questions and explaining the relationship between R value and halving time! 🙏

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