A Chicago shelter that houses young immigrant children confirmed Tuesday that at least 37 children have tested positive for coronavirus.

Officials at Heartland Human Care Services, a division of Heartland Alliance, say 17 children and two staff members initially tested positive for the virus at the facility in the city’s Bronzeville neighborhood.

On Tuesday, officials released additional details, saying that 37 of the 69 children housed in Heartland’s Chicago-area shelters have tested positive for the disease.

According to Pro Publica, the outbreak is the largest outbreak of the virus in any shelter for immigrant youth in the United States.

Melissa Sanchez, a reporter at Pro Publica who has reported for several years on detention centers for children in Chicago, says officials reached out to her Thursday.

“Kids are pretty tightly packed. They share communal space,” she said. “So it is not surprising that an infection that did get into this place would spread rapidly among all of them.”

Heartland runs three facilities in Chicago, which house a total of 69 children.

In a statement, officials from Heartland say they immediately took action after the first positive test was reported, aiming to obtain tests for all children in their care, whether or not they were experiencing symptoms.

“At the first indication of COVID-19 symptoms in our program, we aggressively moved to obtain testing for all the children in our care – even those who are asymptomatic – which goes even beyond the CDC recommendations. We did this to ensure the highest quality of care to our participants and to safeguard our staff as well,” the group said in a statement.

Staff at the facility undertook a series of other measures to help limit the spread of the virus. Staff who interact with residents at the facility are being provided with N95 masks, gowns and gloves, and a series of social distancing measures are in place, including moving participants to an isolated environment if they show any symptoms of the virus.

Staff working on floors where children tested positive are being asked to stay home from work, with pay, for the next two weeks, according to the company.

The facility has not taken in any new children since March 20, according to officials.

Dan Ackerman, who works for Chicago’s chapter of the Democratic Socialists of America, is among those critical of Heartland’s practices prior to the positive tests, saying that COVID-19 cases were “inevitable” at the facility.

“When we are talking about Heartland and their history dealing with infectious disease….their track record is abysmal,” he said. “It’s really frightening what could be happening behind these doors.”