Ms McCormick, the chief executive of Kent Community Health, said the trust had been “doing lots of recruitment” and that she was “really optimistic” about the progress made.
The staffing situation “did reach a critical point quite quickly” in July, she told BBC Politics South East, after staff left or were off sick within a “couple of days”, including in leadership roles.
She said: “It’s unfortunate that all of those things came together but it was very much on the grounds of safety.”
The trust said December was only a target for reopening and was contingent on staff inductions going smoothly.
The ward’s remaining staff are deployed in community teams or at other hospitals during the closure.