Weeks after COVID-19 vaccines became available to all U.S. adults and months after they were prioritized for high-risk groups, the virus continues to spread in Immigrations and Customs Enforcement detention facilities.

ICE was monitoring 2,043 positive COVID-19 cases within its detained population of 16,721, according to agency data posted Wednesday, indicating roughly 12 percent of its detainees currently have COVID-19. Vaccinations have begun in some facilities, but the pace is slow. And there’s no clear national plan to ensure that the detained population gets vaccinated.

In most states, individuals in congregate settings like jails became eligible for vaccination in the early phases of distribution. But the vaccine rollout in ICE facilities has been sluggish because the agency delegated responsibility to states, and some states may not have prioritized populations held in federal custody.

“The allotment for vaccines for detainees across the entire country is part of the individual state’s allotment,” acting ICE Director Tae Johnson said at a House Appropriations subcommittee hearing Thursday. “That is the current plan. … What priority level inmates and ICE detainees are varies significantly by state.”

Johnson added that ICE considered working with public health authorities to obtain its own supply of vaccines, but that strategy could present issues where ICE detainees are held alongside local inmates.

“There has been really no public communication about who is responsible here,” said Laura Belous, an attorney at the Florence Immigrant and Refugee Rights Project, a group that works with immigrants in Arizona detention facilities. “It’s unacceptable that we’re at this point in the pandemic and they’re still trying to figure out who should be in charge.”

Johnson told lawmakers around 20 percent of ICE detainees have gotten at least one shot, although he said he would have to check on more precise numbers. ICE did not respond to requests for additional comment for this article.

COVID-19 poses an acute threat to ICE detainees, who live in close congregate settings and may struggle with underlying health conditions. A report released Wednesday by the government’s Pandemic Response Advisory Committee outlined the difficulty of controlling the spread of COVID-19 in correctional facilities, noting that many of them were not designed for social distancing or quarantine.

At the start of the pandemic last year, ICE released hundreds of detainees at high risk of complications from COVID-19. But individuals who remained in detention continued to face danger: Throughout the pandemic, multiple ICE facilities have been criticized for violating agency health and safety standards.

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A Department of Homeland Security inspector general report released early last month revealed an array of health and safety violations, including a “critically understaffed” medical center, at the La Palma Correctional Facility in Eloy, Ariz., where 167 detainees contracted COVID-19 throughout the course of the pandemic by the time of the federal audit.

And last week, a second DHS inspector general report found that Pulaski County Jail in Illinois failed to properly enforce precautions like masks and social distancing, did not provide adequate medical follow-up care for detainees with chronic conditions and did not conduct routine wellness checks on detainees in segregation, among other issues.

Inadequate medical care at ICE detention centers underscores the need for proper vaccine education for detainees who might mistrust the medical system, advocates say.

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“We’re talking people who have been detained for a really long time, who have been let down and disappointed multiple times by the medical neglect and COVID outbreaks that were completely preventable, and then they were being approached and told, ‘Come and take this vaccine,’” said Sirine Shebaya, executive director of the National Immigration Project of the National Lawyers Guild, noting that some detainees offered the vaccine have been unwilling to be injected.

At the House hearing Thursday, Johnson said communicating the importance of the vaccine was a priority in response to questions from Rep. Lauren Underwood, D-Ill.

“We’ll certainly make sure we focus on that,” he told her.

Critics say ICE needs to develop a more robust national plan and be transparent about its vaccination rates, pointing to the Bureau of Prisons, which so far has inoculated 171,917 staff and inmates and has updated its website to reflect vaccination rates.

“It really feels like folks in immigration detention have been left out of the vaccination campaign,” Belous said.

Suzanne Monyak contributed to this report.