As I heard it, the mortality rate isn’t 90%, but somewhere around 60%.
Its likely higher. There’s plenty of new cases with people who aren’t dead yet.
That's really not clear. If you take the numbers as given (2,288 people dead, divided by 4,269 cases), the mortality is about 54%. HOWEVER, that underestimates the true mortality because the real mortality is calculated by dividing the number dead by the total of those who have either died or fully recovered. Some number of the 4,269 cases are still sick, and will die. So the mortality is clearly something above 54%.
If we assume that there are still 1,000 active cases, and estimate a minimum of 54% mortality (based on the numbers above), we would get (2288 + 540)/4269, which is 66%.
If we assume there are still 1,500 active cases, then the numbers are (2288 + 810)/4269, or 72%.
The way the WHO is talking, there seem to be way more than 1,500 active cases.