"Cases" is becoming the most dishonest word in the English language.
Traditionally you define a "case" by a patient complaint: I have a cough, I have a sore throat, I don't feel well, etc.
That is the case. If you suspect that a particular virus is the culprit and you test for it and the test is negative, the "case" isn't over. First of all, the test may be falsely negative. Secondly, if the symptom remains, what causes it? The case continues!
Likewise a positive test may be erroneous. Or may not be causal to the patient's problem.
PS the overcrowding in hospitals is based on 3 things
fixing this problem is as simple as making people do their jobs properly
PPS there is a renewed push to favor American medical grads in residency assignments (shocking I know!) The correct answer is not America First, but America Only, and then expatriate the rest