# COVID Odyssey: Spring Spruce up 18 ~ Post#901: Auckland NZ COVID-19 Delta~ Update to Poll 2

## Alan Grace 31 October 2021

The dramatic decrease expected in case numbers as more of New Zealand becomes double-jabbed has not occurred. On Saturday we had 160 new cases and on Sunday 143 new cases, almost all in Auckland.

We therefore need to modify our answer to Poll2. We conclude that 24,000 cases per year will still be a worst-case scenario for Auckland. Since Auckland has around 32% of the country’s population, when we extend this percentage to the whole country, we obtain 75,000 cases as a worst-case scenario. We conclude that the best answer for Poll2 is 90,000 cases. See:

COVID Odyssey: Spring Spruce up 5 ~ NZ COVID-19 Delta Poll 2 results~ How may vaccination rates affect a worst-case scenario?

For Update see:

COVID Odyssey: Spring Spruce up 19 ~ Post#902: NZ COVID-19 Delta~ New calculation method for worst case scenarios

New Zealand now has 75% of the country (over 12) double-jabbed. See:
https://www.health.govt.nz/news-media/media-releases

Once Auckland reaches 90% fully vaccinated (over 12), a new “traffic light” system will be introduced to replace the current Lockdown levels. Here is a version someone has created:

First we look at various percentages:

These results come from this table:

We choose  the day with the highest actual case average (1 September).

We will also use these percentages:

You can find these tables here:

DeltaWorstCaseC

We estimate cases numbers (C) using the formula

C = 1.16 x SQRT(2)^d

where d is the number of days from Tuesday 10 August where d = 0.

We base our estimates from Day d = 22 when we had a total of 687 cases and an estimate of 2375.68 cases.

The three week period annualised becomes 41,292 cases. Note for later, doubling this number gives us 82,584 cases, a good estimate for a worst-cases scenario for New Zealand once 90% of the eligible population (i.e. over 12) becomes fully-jabbed.

687/2375.68 is 28.92% which is 11,940.7 cases p.a. (28.92% of 41,292), say 12,000 cases.

On Day d = 22 the overage case number is 45.8 cases based on the previous 15 days (22-7).

On the last two complete lines of the last table we have an average of 47.6 cases and 65.8 cases respectively and roughly 17,500 and 24,000 cases p.a.

These are 42% to 58% of the 41,291 cases.

We conclude that 24,000 is still a worst-case scenario for Auckland but for all of New Zealand this equates to 75,000 cases.

We conclude that the best answer for Poll2 is 90,000 cases as a worst-case scenario in New Zealand when 90% of the eligible population is double-jabbed with up to 80 deaths possible.

90,000/365 gives an average of almost 250 cases per day (246.6 cases).

In Poll 2 we have:

Labelling the choices a) to f) we conclude that the best ranking for Poll 2 is

a), b), c), d), e), f).

You may also like to look at:

NZCasesDeltaZ91u

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