COVID-19 NZ: Can one person infect almost three others?

We look again at the model in the previous post:

We consider if for most of March one person could on average infect almost three other people.

We see that the model below underestimates the actual spread in New Zealand for most of March.

While cases were isolated in New Zealand once they were identified, Lockdown Level 4 only started at 11.59 pm on 25 March.

The results in this post were not affected by the quarantine (people would have been infected before Lockdown Level 4 began) so please ignore the “with quarantine” in the tables.

Here is the original model:


Below is the data that represents the model:
(the highlighted column shows how 5 people could infect 368 others.


How can a Coronavirus out-spread from 5 to 368 people in 5 Cycles (Credit: The New York Times)?

If 5 people with new coronavirus can impact 2.6 others each, then 5 people could be sick after 1 Cycle, 18 people after 2 Cycles, 52 people after 3 Cycles and so on. See:

We note that for this model Ro = 2.6

In New Zealand the spread appears far worse than in the above model.

Here is a similar model for New Zealand:


For simplicity we have retained the values 5 and 368.

Instead of a cycle length of 6 days the above model has a cycle length of 5 days.

Instead of a total of 368 people infected after 5 cycles, we have close to 368 (359) new cases alone during the fifth cycle.

Instead of 24  (6 x 4) more days the above model results occur after 20 (5 x 4) more days.

Instead of 2.6, we have a value for R of almost 2.93 (2.929).
i.e. one person could possibly infect almost 3 others.

Below is the graph for the model:


My other COVID-19 posts can be found here:

Data for my posts can be found at:

I share my posts at:

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