Reason of pandemics

According to the theory of karma,an individual receives the punishment for one's past deeds. Now my question is the whole world is going through a massive unprecedented time,not only corona but severe issues already took place this year,which clearly bore the same effect on every person,does that mean the whole mankind is being punished for their past deeds? If so why don't these pandemics persist eventually? Why only after a certain period of time?