Daily incidence
As can be seen in this graph (Figure \ref{the-first-plot}), the trend of the cases grew rapidly till
2nd April, then there was a plateau, and then the number of cases
steadily decreased starting 3rd April. In the absence of any
intervention, the number of cases would have gone upward. New Zealand
started “lock down” or level 4 of the intervention to “eliminate”
the infection in and around 25th March, 2020. This meant that the
effects to reduce the new number of cases even with increased
surveillance and relaxed criteria took about 10 days to take effect.
Note that this roughly or on average the time it takes an infection to
manifest from first infection. This suggests that despite limitation in
the number of tests being conducted, the tests were on track to identify
and estimate the true number of cases.
Here are the details of these parameter estimates as of now: