i doubt its concern over the intamates' well being that put them this early on the vaccination priority list, it probably has to do with keeping the prison staff safe and keeping them working.

If entire shifts of correctional officers contract the virus its almost a certainty that the people coming in will be getting double time to cover.

also the inmates might not have access to proper facilities if they do contract the virus. Bringing them to a normal hospital is either out of the question or causes logistical issues with keeping the public and the hospital staff safe if a troublesome/difficult inmate has to be brought to a public hospital.