WASHINGTON (AP) — Close to half a million people who lost their health insurance amid the economic shutdown to slow the spread of COVID-19 have gotten coverage through HealthCare.gov, the government reported Thursday.

The numbers from the Centers for Medicare and Medicaid Services come as the Trump administration is expected to file written arguments in a Supreme Court case to overturn the Affordable Care Act. That would jeopardize coverage for some 20 million Americans and put at risk protections for people with preexisting health problems.

Thursday's figures are partial because they don't include sign-ups from states that run their own health insurance marketplaces. Major states like California and New York are not counted in the federal statistics.

An estimated 27 million people may have lost job-based coverage due to layoffs, and it's unclear what — if anything — they're turning to as a fallback. People who lose employer health care are eligible for a special sign-up period for subsidized plans under the Obama-era law. Many may also qualify for Medicaid.

The Trump administration has been criticized for not doing as much as states like California to publicize these readily available backups. In response, administration officials say they have updated the HealthCare.gov website to make it easier for consumers to find information on special sign-up periods.

Thursday's report from the government showed that about 487,000 people signed up with HealthCare.gov after losing their workplace coverage this year. That's an increase of 46% from the same time period last year.

In the case before the Supreme Court, Texas and other conservative-led states argue that the ACA was essentially rendered unconstitutional after Congress passed tax legislation in 2017 that eliminated the law’s unpopular fines for not having health insurance, but left in place its requirement that virtually all Americans have coverage.

After failing to repeal “Obamacare” in 2017 when Republicans fully controlled Congress, President Donald Trump has put the weight of his administration behind the legal challenge.

The Trump administration’s views on what parts of the ACA might be kept or replaced if the law is overturned have shifted over time. But in legal arguments, it has always supported getting rid of “Obamacare” provisions that prohibit insurance companies from discriminating against people on account of their medical history.

Nonetheless, Trump has repeatedly assured Americans that people with preexisting conditions would still be protected. Neither the White House nor congressional Republicans have specified how.