BOSTON (CBS) — Massachusetts is now rolling out coronavirus vaccinations to prisons and other congregate care settings.

There are about 11,000 inmates and staff at Department of Corrections facilities. It’s expected to take about three weeks to give vaccines to everyone in the system who wants it.

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Group homes, shelters and residential treatment programs can also begin vaccinations.

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“These facilities are prioritized because they serve vulnerable populations in densely populated settings,” Gov. Charlie Baker said at a news conference last week.

As of Thursday, Massachusetts had administered 239,000 vaccines.

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Also on Monday, Gillette Stadium officially opened as the state’s first mass vaccination site for first responders in the state.