The Oklahoma Department of Corrections is up to five agency staff and one inmate who are positive for COVID-19.
Four facility staff members across the state and a probation and parole officer now have the illness; along with an inmate at Jackie Brannon Correctional Center.
DOC's first case of COVID-19 was reported last week, a worker at Joseph Harp Correctional Center.
On Sunday, the DOC restricted inmates statewide to their cells to help limit the spread of the coronavirus. Inmates will have food and medicine delivered to them. Activities like showering and making phone calls will be done on schedules.
Prison officials called the move "aggressive but necessary."
The DOC began developing its coronavirus response March 13 by suspending all in-person visitation and volunteer access to facilities. Since then, officials suspended the intake of new inmates, started daily health screenings of workers, and switched Oklahoma Correctional Industries to making masks and hand sanitizer for inmates and prison staff.