This widely varies by countries, as well as often states. It entails what criteria you use for your statistic and how you collect the data. Because unfortunately data collection is one of those things that is assumed to be trivial, but actually quite difficult and costly. Especially in the beginning, you just took the rate of positively tested patients. Because you could do so at a single point in your hospital, the testing center. Figuring out information concerning individual patients means having to collect this information for every individual as well.
Let me also point out that this wasnt some grand failure. We were in a situation in which what ever information we could get was really helpful. But you have to be aware, that there is not magic box somewhere that spits out perfect information. All data collection has its limitations, its why we still know very little about long covid. Because getting that data is incredibly difficult, especially at scale.