Some 500,000 children and families have had their Medicaid coverage reinstated after many states improperly terminated their enrollment because of a systems issue, the Centers for Medicare and Medicaid Services said Thursday.

At issue is the states' use of existing data to automatically determine the eligibility of certain Medicaid recipients as they review all their enrollees' qualifications after a three-year Covid-19 pandemic pause. Some states were considering entire families as a whole without taking into account that the household income thresholds for children are higher.

Late last month, the agency told every state and territory to check their systems and make sure that they were evaluating each member of the household individually. Some 29 states and the District of Columbia so far responded that they had this issue and were required to pause disenrolling residents in this situation and restore the coverage of those already affected.

"By making sure the systems glitch is fixed in states across the country, we will help stop more families and children from becoming disenrolled simply because of red tape," said CMS Administrator Chiquita Brooks-LaSure. "This will help strengthen access to Medicaid, not just during this very challenging renewal transition, but also in the long term."

CMS did not have a breakdown of how many children were among the 500,000 people who regained their coverage, but said it was "a significant number."

Asked whether those reinstated could be disenrolled again at a later date, CMS said it cannot speculate on state action. Some states are expected to have the problem corrected by the time they review the next batch of residents in October, while others will take much longer to address the issue, CMS said.

States are in the midst of reevaluating the eligibility of more than 87 million people in Medicaid and several million more in the Children's Health Insurance Program and terminating those who no longer qualify for the first time since the Covid-19 pandemic began. Congress had barred states from winnowing their rolls, in exchange for enhanced federal funding. But that prohibition ended on April 1.

Since then, at least 7.2 million people -- including at least 1.4 million children -- have been disenrolled from Medicaid as of September 20, according to KFF. Nearly three-quarters of them were dropped for so-called procedural reasons. This typically happens when enrollees do not complete the renewal form, often because it may have been sent to an old address, it was difficult to understand or it wasn't returned by the deadline.