[Introduction to SIR model] Consider the fitting result of Diamond Princess ♬

The data I was interested in was the data from the Diamond Princess issue. I wondered if there was any beautiful data left, but I was disappointed. However, I can do it for the time being, so I tried fitting it. The method is the same as the previous [Introduction to SIR model] COVID-19 data fitting ♬.

Diamond Princess data

As shown below, the cure rate has exceeded 80% and is ending. The mortality rate is about 1.4%, so I think it's a proud number compared to the current situation in each country in the world.

Fitting result

So, I immediately tried fitting with the previous SIR model. The result is as follows. N = 5 * N0, that is, 5 times that of infected people. Actually, I think that there were about 3,700 crew members, but since the additional target people such as medical staff are unknown, I roughly estimated it and increased it by five times. Again, the healer curve is discarded. If you try to match at the same time, you will not be able to fit at all.

The obtained parameters are as follows. Compared to the values of each country, it is a large value.

{\begin{align}
\beta &= 1.04e^{-4}\\
\gamma &= 1.49e^{-1}\\
N &= 3610\\
R0 &= 2.52\\
R(27.3.2020) &= 0.29\\
\end{align} 
}

Evaluation of results

In other words, it can be seen that infection and healing (actually quarantine) progressed quickly. That's right! In the SIR model, if infected, the infected person will not be infected once the infected person is quarantined, and in this case it is removed. Therefore, again, the healer interpreted that the removed people would heal by another route and would recover independently of this equation. Considering this, the case of Diamond Princess is special, but I think it can be evaluated that good measures have been taken.

Summary

・ Displayed the data of Diamond Princess ・ Fitting of the number of infections was carried out using the SIR model. ・ Discussed the effect of quarantine

・ Evaluate the results of each country based on this discussion