The chief doctor at Rikers Island sent an unsettling warning to law enforcement officials on Monday night, saying it’s “unlikely” that even herculean efforts by health professionals inside the New York jail can quell the rapid spread of the novel coronavirus within its walls. Rikers is a “public health disaster unfolding before our eyes,” he wrote.

In a Twitter thread addressed to the district attorneys in the city’s five boroughs, the doctor, Ross MacDonald, urged prosecutors to support the continued release of vulnerable inmates to avoid a public health disaster. At least 167 inmates and 137 corrections staff and health workers have tested positive for the virus, according to the New York Times.

“I am raising this alarm for a reason,” MacDonald, chief medical officer of New York City’s correctional health services, wrote. “I simply ask that in this time of crisis the focus remain on releasing as many vulnerable people as possible.”

MacDonald was responding to a letter the district attorneys in all five of the city’s boroughs sent to Mayor Bill de Blasio (D) and his corrections commissioner on Monday, which was reported in the New York Times and New York Post. The prosecutors said they did not feel the mayor or city officials were heeding their public safety concerns for some releases, reflecting an ongoing debate about how to best balance public safety against public health.

While thanking the district attorneys for their collaboration, de Blasio said Sunday that more than 650 inmates have been released, mostly those with health risks making them vulnerable to the virus, those jailed on parole or probation violations and those charged with nonviolent offenses. But on Monday, the prosecutors said some inmates under review for release at the city’s urging are charged or convicted of domestic violence or sex offenses, leaving them worried for victims. They also worried about the public perception of the jail’s ability to handle the pandemic.

“At this point, the seemingly haphazard process by which at-risk inmates are identified, and the reports that those released may include violent offenders, are creating a public perception that our city’s jails may be incapable of providing sufficient health care for the remaining population of inmates,” the letter said, according to the Post. “We believe this perception is wrong.”

MacDonald’s unsettling rebuttal: That perception actually may not be wrong.

“The only part of the letter I can speak directly to is their failure to appreciate the public health disaster unfolding before our eyes,” he wrote.

In the sprawling complex of gray concrete jail buildings housing more than 4,600 people, the novel coronavirus is spreading at a higher rate than it did in Wuhan, China, in Italy and in New York City, now the hardest hit metropolis in the world, according to a Monday report by the Legal Aid Society. The legal aid group found the rate of infection within the jail was about 3.6 percent, or about 36 infections per 1,000 people. That’s compared to a rate of infection of 0.44 percent, or 4.43 infections per 1,000 people in New York City, according to the report.

MacDonald pointed to the district attorneys plea that the city “immediately reassure the public and the courts that the city’s jail system is capable of appropriately managing the health needs of the remaining inmates, in a manner consistent with recent guidance from the CDC for managing covid-19 in correctional and detention facilities.”

He said Rikers Island had been following guidelines from the Centers for Disease Control and Prevention long before the outbreak happened and while it approached but added that following the guidelines has not been nearly enough to stop it.

“Here’s the important part: infections in our jails are growing quickly despite these efforts,” he wrote.

The first case appeared in the jail 12 days ago, and “in that space of time we have moved mountains to protect our patients,” he said. Nearly 800 inmates have been quarantined in New York City jails, mostly on Rikers Island, the New York Daily News reported Saturday. But the thousands of others remaining are physically incapable of social distancing like free people, as MacDonald has previously warned.

They share bathrooms and showers and cafeterias, cramped cells and telephones and pullup bars, allowing the virus to easily spread from person to person. Inmates have described feeling trapped, unable to protect themselves without adequate cleaning supplies, soap, masks or gloves, while guards and staff are equally “terrified.” One inmate at Rikers told the Times, “We’re left for dead. We’re just stuck here.”

Unfortunately, MacDonald said, as the jail’s chief doctor, he can’t provide the assurance the district attorneys are looking for.

“This is not a generational public health crisis, rather it is a crisis of a magnitude no generation living today has ever seen,” he wrote. “It is possible that our efforts will stem this growth, but as a physician I must tell you it is unlikely. I cannot reassure you of something you only wish to be true.”

MacDonald said all he can assure is he and the other health-care professionals will “give our all through every brutal day of this crisis.”

MacDonald joins a chorus of advocates, health professionals and defense attorneys calling for the release of as many vulnerable and nonviolent inmates as possible from jails across the country to avoid a public health catastrophe.

About 1,700 inmates have been released from the Los Angeles County Jail, bringing the population to 14,500 with zero infections reported so far, according to the Los Angeles Times. The Chicago Tribune reported Tuesday that the Cook County Jail’s population is down about 600 since mid-March, bringing the population to 5,000. At least 134 detainees in the jail have tested positive as of Monday, the Chicago Sun-Times reported.

“It was like Disneyland for coronavirus,” one man who tested positive inside the jail told the Sun-Times. “Once it’s in, it’s going to go crazy.”

Other counties have met some degree of resistance to mass releases from law enforcement officials, wary that some inmates who are vulnerable to the coronavirus may also be charged with violent crimes.

That dilemma was apparent in Texas on Sunday, when the state’s largest jail in Harris County recorded its first case of coronavirus.

Gov. Greg Abbott (R) issued an executive order banning the release on personal bonds of any person charged with a violent crime or with a violent crime on their record, which some argued violated state law, the Houston Chronicle reported. A federal judge in Houston had also been working with Harris County officials to plan for the release of many nonviolent offenders, but the attorney general’s office also made clear it would oppose any blanket releases, the Chronicle reported.

Abbott said Sunday that “releasing dangerous criminals makes the state less safe and slows our ability to respond to the disaster caused by covid-19.”

In the federal prison system, Attorney General William P. Barr asked prison officials on Thursday to begin assessing older inmates and those with health problems for home confinement. The first federal prisoner died of coronavirus on Monday. Patrick Jones, 49, had been serving a 27-year sentence in a Louisiana prison for possession of crack cocaine for sale too close to a school.