What are closed cases? Only the cases where people have been tested and out of those the number of people that have actually died, right?
But, how can that give you the true mortality rate of the virus, if the majority of people INFECTED with the VIRUS show no symptoms and have not been tested yet? You are just not going to count those people?
That would not give you the true numbers for the mortality rate - far from it!
So, as bad as the situation is right now and the number of people that are dying is terrible, the mortality rate of this virus is much lower than what’s being reported, because very few of us have been tested, so you don’t know the true number of individuals who have been infected - much, much, higher than what’s been reported.
Just because you don’t show symptoms, doesn’t mean you haven’t been infected.
The only way to know, is to test everyone - then you’ll get the true mortality rate.