At least 52,649 prisoners had tested positive for coronavirus by the end of June, which represented an eight per cent rise from the week before, according to data from nonprofit news organisation, the Marshall Project, and the Associated Press.
Of the 52,649 prisoners, at least 35,796 have recovered from the virus, while 616 have died.
Additionally, more than 11,810 staff members have been reported to have contracted Covid-19 and at least 43 of them have died.
The only two states who had not reported any cases of coronavirus inside their prisons by 30 June, were Hawaii and Wyoming.
The amount of coronavirus cases fell in prisons in May, but in June they rose again after Tennessee, Texas and other states reported new outbreaks across jails in their networks.
The increase in Covid-19 cases in prisons has come as positive results in the US have risen dramatically, with the country recording record daily figures above 50,000 in the last week.
States such as Arizona and Texas have been badly hit, and have halted further easing of measures and closed bars again in an attempt to control the virus.
Outbreaks at prisons have been a concern since the start of the pandemic, and many low-risk prisoners, including president Donald Trump’s former attorney Michael Cohen, have left early due to fears they would contract the virus in a crowded facility.
Nicole Porter, director of advocacy for The Sentencing Project, told the AP that most states have only let a small number of prisoners out early, despite overcrowding.
In Louisiana, 1,100 inmates were put forward to have their release date examined, but only 63 have been let out early or are scheduled to be, according to the Advocate.
Ms Porter said that this is not good enough, and added that authorities should be looking to release every prisoner early who is due to leave this year.
“A global pandemic creates a level of urgency that people should not be kept in prison one day longer than necessary,” Ms Porter said.
“Many of those people pose absolutely no threat to public safety and their liberty would have been restored anyway this year.”
Piet van Lier, a researcher for Policy Matters Ohio echoed Ms Porter’s comments and said: “They could save lives by reducing the prison population as the Covid-19 death toll continues to rise behind bars.”
According to a tracking project hosted by Johns Hopkins University, there are now more than 2.7 million people who have tested positive for coronavirus in the US. The death toll has reached at least 129,192.