WASHINGTON (CNN) -- A severe flu pandemic "would almost certainly lead to a major economic recession," according to a new report from a nonpartisan, nonprofit organization. The report, titled "Pandemic Flu and the Potential for U.S. Economic Recession," projected that a pandemic would kill 2.25 million people and force 87.75 million people to miss work for three weeks That could cause the U.S. gross domestic product to drop more than 5.5 percent, resulting in an economic loss of $683 billion.