Millions will lose health insurance starting Saturday. But they might not know it.

 Saturday marks the first day states can remove people from Medicaid rolls.

Millions of people will begin to lose their health insurance on Saturday, as five states begin the unwinding of a pandemic-era protection that kept people from being removed from the Medicaid rosters.

During the public health emergency, states were required to keep people on Medicaid without the often yearly reapplication process normally in place. But now that the public health emergency is winding down, so are the Medicaid rolls.

"We're now in a position within just a couple of days where states can begin to disenroll people — to redo their rosters for Medicaid — and this continuous coverage requirement is no longer going to be in place," Dr. Avenel Joseph, vice president of policy for the Robert Wood Johnson Foundation, told ABC News.

The issue that Joseph and other advocates are concerned about is that not enough people know they're about to get kicked off their coverage.

For Jeffrey Jackson, a 62-year-old Medicaid beneficiary in Arkansas who faces losing that coverage in a matter of days, that could be a "nightmare."

Arkansas is one of the five states that will start removing people from coverage on April 1, along with Arizona, Idaho, South Dakota and New Hampshire.