As well as the dismissals, NUH said 15 final written warnings and two first written warnings have also been issued in total.
Two cases were found to have no case to answer and no action was taken.
The trust said action had been taken against “doctors, nurses, registered healthcare professionals and other staff” and that independent regulators such as the Nursing and Midwifery Council and General Medical Council, the Information Commissioner’s Office, and Nottinghamshire Police had been informed.
A new system, currently under testing, is being implemented to protect patient records in future and alert the trust of potential breaches.
A Your Responsibility, Your Actions, Their Privacy campaign has also been carried out to educate staff about data protection and the “serious consequences” of not following the rules, it added.
Shehmar said: “We will continue to investigate inappropriate access to these records and take action as and where necessary.
“Alongside this, we are doing all we can to educate our staff on appropriate access and how to keep the records of our patients safe. We are also introducing a new system which acts to detect possible data breaches.
“While the actions of these staff members are disappointing, we know that this represents a small number of our wider workforce.
“We know staff across the trust are listening, learning and doing what they can to ensure that only lawful and justified access takes place in our hospitals.”
NUH said investigations were continuing, including into inappropriate access of the files of the surviving victims of the attacks – Wayne Birkett, Sharon Miller and Marcin Gawronski.