County health officials Tuesday gave supervisors an inkling of what repeal of the Affordable Care Act and replacement with a Republican alternative would mean for Marin.

“Marin would be estimated to lose approximately $100 million if we were to move to this structure,” said Kari Beuerman, the county of Marin’s director of social services.

Beuerman said that is because the Republican plan released Monday calls for block-granting Medicaid, which in California is known as Medi-Cal.

Beuerman said the plan would impose a per capita cap on the federal government’s contributions to Medi-Cal, “which means that the money that California receives from the federal government would be capped for program participants.

“We think California would be at a real disadvantage if things move to that structure,” Beuerman said. “It would be based on historic funding, which has been historically low in the state of California.”

Grant Colfax, county director of Health and Human Services, said, “We’re waiting for the Congressional Budget Office to assess the cost and the potential number of people who will lose insurance; we’re very, very concerned about that.”

Beuerman said since the advent of the Affordable Care Act in 2014 — under which more people became eligible for Medi-Cal — the number of people enrolled in the program in Marin grew 118 percent from 18,406 to 40,128 individuals.

But Beuerman said Marin’s enrollment in Medi-Cal increased by a mere 3 percent during the recent open enrollment period from November 2016 to January 2017.

“We’re still analyzing why it was such a modest increase,” Beuerman said. “It’s possible we’ve reached a saturation point, where all of the people who qualify for the program are enrolled in the program, which would be a great thing.”

Beuerman said, there are, however, factors at the federal level, such as the election of President Donald Trump, that could be affecting people’s willingness to seek such benefits.

Beuerman said 30 percent of the county’s public assistance population are non-citizens, and immigrant communities in Marin are very fearful.

It’s expected that under the Republican plan fewer people would be able to afford health insurance, since the plan calls for reduced tax credits to help people pay for health insurance.

Beuerman said, “Basically what we’re looking at is vulnerable people with the potential of losing their health coverage — poor people, homeless people, women, children, seniors, people with disabilities.

“What we fear is that those populations would go back to accessing health care at hospital emergency rooms, and the chaos and cost associated with that,” she said.

Colfax said, “Our message to the communities we serve is that we stand with them. We are currently enrolling people in our programs, and we will do everything in our capacity to maintain the system.”