The Trump administration proposed a rule last year to change how immigration officials determine whether an immigrant is a "public charge" -- a status that means the person is "primarily dependent" on government assistance -- which could contribute to certain green card or visa applicants being turned down if they have low incomes or little education.
Fear around the proposed change to the definition of "public charge" also could put the medical and nutritional needs of millions of children at risk, according to a new study.
The proposed rule, announced in September, would expand the public charge concept to include more widely used benefits, including Medicaid, food stamps, housing assistance and the Medicare drug subsidy for low-income seniors.
The proposal applies to those looking to come to the United States and those already here and seeking to extend their stay. Even if immigrants decide not to use public benefits they may be eligible for, the government could, under the proposed rule, still decide they are likely to do so "at any time in the future" and thus reject them from the United States.
The administration says the proposed revamp of the public charge rule is designed to ensure immigrants can support themselves financially.
Now the new study, published in the medical journal JAMA Pediatrics on Monday, suggests that, if implemented, the rule change would lead to some 1.4 million children being disenrolled from Medicaid, the Children's Health Insurance Program (CHIP) or food assistance; specifically, the study estimated between 800,000 and 1.9 million children.
Families could disenroll their children because they fear their immigration status could be questioned due to their use of certain benefits.
"What we know from other studies is that because there's so much fear and confusion about this particular rule that many people are disenrolling from these benefits even when the rule doesn't apply to them," said Dr. Leah Zallman, assistant professor of medicine at Harvard Medical school and director of research at the Institute for Community Health, who was first author of the study.
"So we, like others, considered non-citizens -- even though non-citizens are not all subject to the rule -- to be at risk of disenrolling themselves or their family members," said Zallman, who is also an internist and practices primary care at Cambridge Health Alliance in Massachusetts.
The proposed rule change itself "only applies at the point of entry or when getting green card status and even then there's some exclusion," she said. "So I think it's really important to highlight that it only technically applies to a small portion, and that it's neither finalized nor in effect nor will it be retroactive."
The National Immigration Law Center recommends that families planning to apply for a green card or visa continue to use health, housing and nutrition programs when needed.
Analyzing data from the 2015 Medical Expenditure Panel Survey, Zallman and her colleagues estimated how many children in the United States currently enrolled in Medicaid, CHIP or the Supplemental Nutrition Assistance Program (SNAP) may be at risk of disenrollment due to living with an adult who is a non-citizen. It was found to be about 8.3 million children.
The researchers then determined 5.5 million of these children have a specific medical need -- including 615,842 with asthma, 53,728 with epilepsy, 3,658 with cancer and 583,700 with disabilities.
The researchers also assumed a 25% disenrollment rate among at-risk children. That rate was modeled after previous studies that measured disenrollment rates among eligible immigrants around the time of the 1996 welfare reform.
The study had some limitations, including that the researchers were unable to estimate the number of children in households receiving housing assistance or Medicare part D low-income subsidies. Additionally, the 25% disenrollment rate estimate came from previous research on welfare reform, a different scenario than the proposed "public charge" rule change.
The researchers wrote in their study that, if the public charge rule is finalized, disenrollment rates might be even higher than they estimate.
Kelly Whitener, an associate professor at the Georgetown University McCourt School of Public Policy's Center for Children and Families in Washington DC, said that she was not surprised to see such a large number of children potentially at risk of losing benefits.
"The 8.3 million number needs to be in context with the 1.4 million that they would expect to disenroll using the 25% disenrollment rate," said Whitener, who was not involved in the study.
"One in four children in the US have an immigrant parent, so that's a huge number. Then once you try to whittle down to how many children have a non-citizen parent, how many of those children use Medicaid and CHIP, it doesn't surprise me that the number would still be quite large," she said.
"I think that the public charge rule, even in its proposed form, together with all of these other activities happening -- around increased ICE raids, the prolonged humanitarian crisis at the border -- all of these things are feeding into a climate of fear that is developing into toxic stress for immigrant communities," she added. "That's going to have long-lasting impacts on the development of children, far beyond what you can more carefully monitor in terms of enrollment in certain programs."
The change in the public charge immigration rules likely will have a "dramatic effect" on children residing in the United States with non-citizen adults, explained Dr. Paul Spiegel in an email. Spiegel a professor and director of the Center for Humanitarian Health at the Johns Hopkins Bloomberg School of Public Health in Baltimore.
"The public health effects could have larger repercussions beyond those children and their families," said Spiegel, who was not involved in the study.
"The limitations of the study point towards a likely underestimation of the children who will be affected by the administration's change in the public charge immigration rules," he said. "The findings that approximately 8.3 million children who are currently enrolled in Medicaid and CHIP or receiving SNAP benefits are potentially at risk of disenrollment, of whom 5.5 million have specific medical needs is startling as to their magnitude and implications."
CNN's Maegan Vazquez, Tami Luhby and Tal Kopan contributed to this report.