COVID Odyssey Addendum
Summer has ceased Autumn’s awesome
My thoughts come least my mind’s caught numb
I feel like an April fool
I have sealed my time capsule
Before adding my addendum
Alan Grace
26 March 2022
The COVID Odyssey website has become an open Time Capsule:
Alan Grace: COVID Odyssey Time Capsule for aaamazingphoenix.wordpress.com – Warning: Most Links within posts will go to the original site: aaamazingphoenix.wordpress.com
A version of this post can be found here:
COVID Odyssey: Autumn Addendum Post #971~ COVID Odyssey Time Capsule Addendum – COVID Odyssey: Alan Grace’s vir[tu]al journey (wordpress.com)

This addendum covers:
- NZ now has around 600,000 cases of COVID-19
- Ro can be estimated by r^1.2 where r is a daily increase factor in case numbers

This PDF may be easier to read and contains a wider range of values:
CasesReRoC5
The actual value for Ro will lie between our values calculated for Re and Ro.
We could also estimate Ro using r^1.1, the geometric mean of r and r^1.2. We obtain:
CasesReRoD
In the first 2020 Outbreak New Zealand, r =1.4 and hence r^2 = 1.96. This is close to 2 so we thought that when r = 1.4, for Ro, r was close to SQRT(2). At a minimum this could be the case. Let z = ln( SQRT(2) ) / ln(1.4) and use r^z in our formula where z = 1.030021359. This gives the result we require when r = 1.4. We obtain (see image below):
CasesReRoE
CasesReRoE2
(the last two columns show the increase in r when estimating Ro)
CasesReRoE3
(includes Ro/Re)
This provides low estimates for Ro, close to Re as required when r = 1.4. We adopt these estimates.

Both Re and Ro are estimated using this formula:

where n = 10 Days.
For our upper estimate in the range for Ro, substitute r^1.2 for r in the formula.
Please see the WELCOME menu for background and definitions at:
COVID Odyssey: Alan Grace’s vir[tu]al journey – COVID Odyssey: Alan Grace’s vir[tu]al journey investigating/experiencing COVID-19 life (wordpress.com)
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