Visits to a prison have been stopped after an outbreak there caused a "surge" in Covid-19 cases in the area.
There have been 53 cases confirmed at HMP Lowdham Grange in Nottinghamshire's Newark and Sherwood district.
The number of Covid-19 cases in the area is higher than the current national average and the county's public health director said the jail's cases accounted for the "surge".
The prison director said the "priority was to keep everyone safe".
Jonathan Gribbin, director of public health for Nottinghamshire, said: "We've been tracking quite carefully what is going on and we've seen quite a rise in cases across the district.
"There's a total of 53 confirmed cases at Lowdham Grange - 40 prisoners and 13 members of staff - which accounts for quite a lot of that surge.
"A number of measures are in place. At the moment the prison is closed to outside visitors.
"Prisoners are pretty much restricted to their cells. When they are able to leave, they are quarantined in small groups - like households or bubbles."
Mr Gribbin added an "enhanced regime of cleaning" was in place and staff have been issued with face coverings.
The rate of coronavirus infections in the Newark and Sherwood district is 67.8 per 100,000 population.
This compares with the England average of 55 per 100,000.
Mr Gribbin said cases had previously been mostly distributed across Newark but now people were testing positive in nearby villages, including Ollerton and Edwinstowe.
Prison director Mark Hanson said staff were working with the NHS and Public Health England to "implement the best possible strategy to manage the virus".