If we consider the trend lines based on our estimation of the possible
rate of rise in the number of new cases assuming the trend of the growth
in the number of cases were to continue as before, then we see from our
plotting that by April 16th onward, we would see around 70 new cases
everyday. But we do not see that, instead we have trickled down to
around 18 cases in a day (some days may still be high, this is on an
average).
What happened as a result of the lock down and what can we expect?
It is reasonable to believe that when a country goes for suppression of
infection, then the aim is to bring down the effective reproduction
number to below 1.0. In theory, if 100% people comply with the lock
down provisions, then it should happen instantly. But that may not be
the case. So, let’s say enough people comply with the provisions so that
the effective reproduction number drops down to around 0.90 and the
infection is deemed unsustainable. Then, we should expect a slow
regression to zero cases eventually. But how slow or how fast? It cannot
be as rapid as the cases upswung in the first place. Let’s say we study
the trend of new cases for days 30 through 37 (in our case this would be
something like we study from March 28 through April 6) and try to
predict when we can expect the new cases will drop down to zero, so the
total case count will steady with no new cases anymore.
Here is the figure: