MADISON, Wis. — Two additional inmates have died from coronavirus in Wisconsin's prison system, bringing the total number of COVID-19 deaths to 25, according to corrections officials.

The additional deaths come as more than half of the state's roughly 20,000 prisoners have been infected.

Department of Corrections spokesman John Beard said inmates who have tested positive have been medically isolated and those exposed have been quarantined "as space allows." Transfers to and from the prison have been temporarily suspended.

The largest outbreak Thursday was at Oakhill Correctional Institution in Dane County, which had 205 active infections. More than 60% of the inmate population there has been infected, as well as 13 employees.

The outbreak at Oakhill started in December, Beard said. When inmates started showing symptoms and when their tests started coming back positive for COVID-19, DOC brought in the National Guard to conduct mass testing Dec. 14, the State Journal reported.

By mid-December, 20 inmates were infected and by Christmas, the number had risen to 172. The Guard came in for mass testing again on Dec. 28 and Jan. 4, Beard said.