Because it's not being brought into the old folks homes by visitors.

John, 89, has heart attack, gets brought to hospital, picks up Covid there. Recovers from heart attack to return home. Develops symptoms while recovering, later dies (because recovering from a heart attack and getting the flu is no beuno, obviously).
Next week, Maria, Oliver, and Barbara all get the Cov - and all were under increased care because of other medical conditions... Voilà. You've got your death count.