Michael Bigenwald brought to my attention an article in today's Wall Street Journal (page A2) with the headline "Flu Season Threatens Productivity."
Based on the average annual costs of $1 billion to $3 billion in direct flu-related medical costs, such as hospitalizations and medications, and indirect costs of $12 billion for missed worked, David Cutler , a professor at Harvard University estimates that the flu's effects on the economy could approach $20 billion this year.
How big as that number? Something on the order of 0.2% of GDP. Not huge, but too many of those and pretty soon you might be talking about real money.