A Chicago judge on Thursday rejected a bid by inmates to be released or transferred from a jail housing 4,500 detainees which has emerged as one of the largest coronavirus clusters in the US.

Cook County Jail in the US's third-largest city has 276 inmates who have tested positive for COVID-19, along with 172 staff members of the Cook County Sheriff's Office, which oversees the facility.

However, the jail acknowledged those numbers are likely an undercount, as the majority of its inmates have not been tested.

The jail has seen one prisoner death so far from complications of the virus, but lawyers had filed a petition before a federal court for mass transfers.

In a 37-page ruling handed down on Thursday, District Judge Matthew Kennelly ordered Cook County Sheriff Tom Dart to implement new policies to keep inmates safe but rejected the call for them to be moved en masse.

Kennelly acknowledged the sheriff's challenge, calling it "an extraordinary difficult task," but ordered soap and sanitizer provided to inmates and staff, and facemasks for inmates in quarantine with COVID-19 symptoms.

The judge noted the infection rate in Cook County was 1.56 per 1,000 people. In the jail, as of Monday, it was 50 per 1,000 people, he wrote.

The lawsuit, filed April 3, sought a mass release or transfer of elderly and medically compromised inmates.

Dart has said his office has already taken steps to protect inmates and staff, while also releasing several hundred inmates charged with or convicted of non-violent crimes.

Dart said his dilemma is that 70 percent of inmates have either been convicted or are accused of violent crimes.

'Presumed innocent'

Jeffery Pendleton, 59, who was being held on drug and weapons charges, appears to have died from complications of COVID-19, Dart has said.

Pendleton, who had 15 previous convictions, including as a sex offender, was jailed because he could not come up with $5,000 -- or ten percent of the $50,000 bond set by a judge.

The Cook County Public Defender's Office filed an emergency motion for Pendleton's release on March 26 but was denied, four days before he was hospitalized after testing positive for the virus.

"He was and always will be presumed innocent. He died awaiting for his day in court. He should have been sent home," tweeted Amy Campanelli, an attorney at the Chicago Community Bond Fund, a group that advocates for the elimination of the cash bond system. 

Along with releasing more inmates, Dart said on his website that he had taken steps to protect them. Measures included early screening and testing of detainees, and increasing availability of personal protective equipment (PPE) and sanitation supplies.

"Detainees who test positive are isolated and receive thorough medical attention and cellmates are quarantined and monitored," he said.

Dart also banned inmates' families from visiting and requires attorneys and clergy members to be screened for virus symptoms.

Incoming inmates are housed in tiers where staff observe for symptoms for seven days before they are transferred to the general population. Cleaning has also increased through the jail and inmates are being educated about preventative hygiene.

Yet, those actions, along with creating an 500-bed quarantine facility and moving inmates from double cells to single cells to increase social distancing, did not stop the spread of the virus -- nor has it satisfied staff who feel slighted by the focus on inmate safety.

'We have to stay'

"We have 150 staff members who have tested positive for the virus and everyone is saying we should release all the inmates. They get released, yet we have to stay," said one sheriff's deputy who has worked in the jail for nine years and spoke on condition of anonymity.

As for the inmates, he said only 60 have been moved to the 500-bed quarantine facility. Another worker at the jail confirmed that figure. 

The sheriff's deputy added that jail staff did not receive protective gear for two weeks after the first cases were identified at the facility and fears he might bring it home to his wife and children.

"Bringing the virus home is my biggest fear. I have nowhere to isolate away from my family unless I sleep in my car."

The Cook County Sheriff's spokesman denied that staff have not been provided with sanitation supplies or protective equipment, adding that front-line workers can get tested onsite.

"We are very concerned about the health and safety of our staff," he said in a statement to AFP. "To say they don't have supplies and don't have an avenue to get them is completely false."

"We remain in daily contact with the unions that represent staff members, and will continue to work with them to protect our employees and fulfill our obligation to provide a safe, secure jail."