BILLINGS, Mont. (AP) — The Montana State Prison reported its sixth death from a coronavirus outbreak Wednesday, while a prison in Dawson County reported the same day an outbreak of at least 65 people.

The state Department of Corrections said in a statement that a 60-year-old man died from the virus on Dec. 11 and that there are no ongoing cases in the Montana State Prison.

That marks the end of an outbreak that infected 477 inmates and 162 employees starting in October, the Lee Newspapers of Montana reported.

Dawson County Sheriff Ross Canen said in a statement that a facility has 53 inmates and 12 staff members who have tested positive for the coronavirus. Protocols have been implemented in an attempt to mitigate the spread, including a mask mandate for inmates when they are outside of their cell and for every staff member, the Billings Gazette reported.

The number of infections is thought to be far higher because many people have not been tested, and studies suggest people can be infected with the virus without feeling sick.

For most people, the new coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some — especially older adults and people with existing health problems — it can cause more severe illness, including pneumonia, and death.