(NewsNation) — At least two million children have been disenrolled from Medicaid; experts worry many of them remain uninsured.

The issue comes with a process called unwinding. During the COVID-19 pandemic, a federal program prevented most people from losing Medicaid coverage even if they had a change in income that would normally disqualify them.

But now that the emergency provision has expired, states are starting to recheck the eligibility of all people receiving Medicaid.

However, it’s not clear everyone being removed from Medicaid rolls is actually ineligible for coverage. Data from the Kaiser Family Foundation found 72% of those unenrolled during unwinding were dropped for procedural reasons, like errors in paperwork, not because they were actually ineligible.

The Biden administration also found an error in how states were conducting renewals, with many doing so on a household basis rather than an individual basis. If even one member of a household appeared ineligible, some states were requiring all members of the household to fill out renewal forms. If those weren’t received, all people in the household were dropped.

Children are more likely to be affected by the error because the income thresholds for Medicaid are higher for children than for adults.

As states have reported the number of disenrolled recipients, millions of children have been dropped from the program. That doesn’t necessarily mean those children are uninsured; some may have been dropped because the family enrolled in private insurance or moved out of state.

Children who are dropped from Medicaid may also be eligible for the Children’s Health Insurance Program, designed to cover kids in families who make too much money to qualify for Medicaid but not enough to purchase private insurance.

But the number of kids newly enrolled in CHIP is much lower than the number dropped from Medicaid. That has left experts concerned that those children are going without insurance as the country heads into winter, a time when respiratory viruses tend to circulate.

Even if parents are able to reenroll their children, a lapse in coverage can be costly or leave kids without necessary medication that’s too expensive for families to purchase out of pocket.

The Biden administration has instructed states to determine eligibility on an individual basis rather than a household one, but it’s unclear how much impact that will have with so many already dropped from Medicaid.