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 percent higher than the highest previous increase, which occurred during the recession of 2008 and 2009, when 3.9 million adults lost insurance.