WASHINGTON >> The coronavirus pandemic stripped an estimated 5.4 million American workers of their health insurance between February and May, a stretch in which more adults became uninsured because of job losses than have ever lost coverage in a single year, according to a new analysis.

The study, to be announced Tuesday by the nonpartisan consumer advocacy group Families USA, found that the estimated increase in uninsured workers from February to May was nearly 40% higher than the highest previous increase, which occurred during the recession of 2008 and 2009, when 3.9 million adults lost insurance.

“We knew these numbers would be big,” said Stan Dorn, who directs the group’s National Center for Coverage Innovation and wrote the study. “This is the worst economic downturn since World War II. It dwarfs the Great Recession. So it’s not surprising that we would also see the worst increase in the uninsured.”

Families USA is one of a number of groups trying to estimate the number of people who have lost insurance during the pandemic; definitive data will not become available until mid- to late 2021, when the federal government publishes health insurance estimates for 2020. The analyses vary, but all reach the same grim conclusion: More people lack insurance than ever before.

The nonpartisan Kaiser Family Foundation has estimated that 27 million Americans have lost coverage in the pandemic; that study took into account family members of the insured. Another analysis, published Monday by the Urban Institute and the Robert Wood Johnson Foundation, projected that by the end of 2020, 10.1 million people will no longer have employer-sponsored health insurance or coverage that was tied to a job they lost because of the pandemic.

The studies come in the thick of the campaign season, when health care — and in particular the future of the Affordable Care Act, popularly known as Obamacare — will be a major issue. Democrats and their presumptive presidential nominee, Joe Biden, want to expand the law. President Donald Trump has asked the Supreme Court to overturn it.

Four of every five people who have lost employer-provided health insurance during the coronavirus pandemic are eligible for free coverage through expanded Medicaid programs or government-subsidized private insurance through the Obama-era health law, according to the Kaiser Family Foundation.