Long before the coronavirus pandemic, Rashena Carter knew how infection can spread through an institution: Her son, Jewel Scott, had contracted tuberculosis as a teenager while at a Philadelphia youth detention center and, after he was released, spread it to his siblings.

Now, Scott, 20, is at risk again — locked up in a Philadelphia jail since Jan. 3 on a drug-dealing charge and, Carter worries, medically vulnerable to COVID-19 due to his asthma and the lasting damage of TB.

“They’re saying they’re social distancing, but they’re not — because they’re adding more people to his cell,” Carter said. “It was two, now it’s four.”

Scott’s bail was set at just $3,000 unsecured, meaning he could be released without paying anything. But because he was on probation for a previous drug conviction, his arrest represented a possible violation and triggered a detainer — a hold that will keep him incarcerated until a judge decides to release him.

Six weeks after Philadelphia and neighboring counties joined a nationwide movement to reduce jail populations ahead of inevitable institutional coronavirus outbreaks, Scott is one of many who remain behind bars not because they’ve been found to pose a public safety threat, but because of the complexities of their legal-system entanglements.

Philadelphia has reduced its jail population by about 23% since February, a sluggish process that has drawn criticism from defense lawyers and Philadelphia District Attorney Larry Krasner. One by one, judges have reviewed cases, lifting detainers, reducing bail, and approving parole — what Krasner called “the low-hanging fruit.”

In Pittsburgh, by contrast, the jail population is down 31%, which Krasner attributed in large part to the county’s more proactive probation department: “They collected 250 detainers they thought should be lifted and they went to the judiciary with them, with agreement from both sides.”

In Philadelphia, the probation department’s phone line indicates that the office is closed until June 1, and offers no mechanism for probationers to check in remotely. Lawyers said calls to the department have gone unanswered. The unit that processes electronic monitoring, used to release people to house arrest, is not operating, lawyers said, eliminating what some see as a key avenue to safely reducing the jail numbers.

A court spokesperson did not respond to questions about whether the probation department is functioning and why electronic monitoring is not available.

In Philadelphia’s patchwork response, nonprofit bail funds have filled the gaps, posting bail for more than 200 people — and even finding housing for some who were cleared for release if they enrolled in tele-treatment. Reuben Jones, a bail fund organizer, said his nonprofit, Frontline Dads, spent $5,000 to secure apartments for nine people, and was working to add five more beds.

But the bail funds could not help the more than 1,300 people being held on detainers for non-criminal violations, like failing to report or using drugs, or for violations that involved criminal charges of misdemeanors or drug dealing.

“Some have bail as low as $300. But if those detainers don’t get lifted, those people will sit there indefinitely,” Jones said.

One of those defendants with $300 bail, in a transcript of a phone call provided by his lawyers, described making do with scant cleaning supplies — wiping down the phones with a dirty washcloth he’d been using for two months, splitting up bars of soap to share with cellmates.

More than 190 people have tested positive for COVID-19 in Philadelphia jails, however the city said it does not have the resources to conduct widespread testing.

In Montgomery County, which began universal testing of prisoners last week, initial results indicated 18% were positive.

In Delaware County, which reduced its jail roster by about 25%, officials told reporters they expect 40% to 70% of inmates to contract the coronavirus.

Despite the health risks, people in Delaware County continue to be held on detainers for crimes like shoplifting, or for violations including failing drug tests or failing to pay restitution, a lawyer familiar with the situation said.

Rasheed Muhammad, who was on parole when he was arrested in 2018, got his bail reduced in March. But a detainer is keeping him incarcerated through the pandemic.

Muhammad, who was convicted of manslaughter as a teen in 2004, said he has tried to turn his life around. He was driving an informal taxi service, he said, when he agreed to drive two people to the bank. Waiting in the car, Muhammad said, he wasn’t aware that they were cashing bad checks.

All three were arrested, but only Muhammad refused to plead guilty and is still in jail, charged with the checks, drugs, and an illegal gun that was in the car.

“I feel bad for him, because he had nothing to do with it,” said his codefendant Henry Clark, 74, who pleaded guilty and was released on parole.

Now, Muhammad is on “22 and two,” meaning two hours out of cell per day. He’s seen people react wildly — literally climbing the walls to avoid going back in their cell, throwing urine at correctional officers.

He can understand their desperation. He believes he has already had the coronavirus: A few weeks ago, he felt feverish, with a cough, weakness, and diarrhea. Then, for several days, he lost his sense of smell and taste. He said he received Tylenol a few times, but his temperature was checked only once. He never took a coronavirus test.

Whatever made him sick swept through his cell block, he said. “No one over here that I know of has been tested, regardless of whether they were sick or not.”