Did this happen recently with the latest patch because yesterday I did not notice this while playing for a short time.
Unfortunately this whole sickness thing was not made properly, whats the point of having a sickness when you cant go to the hospital or call a doctor to visit you?
Sickness system should have been something like that:
1- each sickness has unique name and symptoms
2- When a sim gets sick he should go to the hospital or call a doctor to visit him
3- Doctor makes a diagnosis
4- Doctor prescribes the medicine/treatment.
5- Every disease has a different treatment not just one single medicine for everything.
6- Treatment can be different: different medicines/ Herbs mixed/ advise of eating a certain kind of fruit or vegetable/ proper rest etc
It is very unfortunate that the whole sickness system was done in a very shallow way.