Much has been made of the potential difficulties businesses face if numerous employees are out sick with the H1N1 "swine" flu. But there has been little information on the economic and other impacts if schools and day care centers continue to close temporarily to mitigate outbreaks.

Closing all U.S. schools for a month would cost the already stressed national economy between $10 billion and $47 billion, according to a new report released today by The Brookings Institution, a nonprofit public policy think tank. It would also cut the health care workforce by 6 to 19 percent if some workers have to stay home to provide child care—a significant hit, as the flu is already expected to put a big strain on the nation's health care system, with predictions that it will infect as much as half the U.S. population and hospitalize some 1.8 million this year.

Schools and day care centers have long been known as germ hotbeds—and the H1N1 flu pandemic is no different. "Closing schools can reduce social contact among kids," Joshua Epstein, senior author of the report and a senior fellow at Brookings, said at a news conference today. And reducing that spread among children, who have proved to be the most vulnerable population for this strain, would mitigate the overall burden on health care.

The government has suggested however, that schools be closed only in the event of a severe outbreak, to avoid a major social and economic disruption. Since the flu strain's appearance in April, some schools and districts have temporarily closed—or instituted recommended dismissals—anyway. And in some cities, such as New York, closing schools has become a heated topic after student and administrator flu-related deaths. Some countries, including Japan, have had broader, government-recommended shutdowns.

About a quarter of U.S. households include a child under 16 years old with no stay-at-home caretaker, leading to about a 10 percent decline in working hours overall in the event of school closures, the authors note in the report, which analyzed in detail who would likely be caring for children, what their employment and wage levels are, and how many hours would be missed. Depending on those variables, the total cost of each student staying home would be between $35 and $157 a week. So closing all schools in New York City for a month, for example, would likely mean a loss of about $1.1 billion.

Aside from economic trade-offs, closing schools' doors can be a catch-22, the authors note. "The most pronounced benefit of school closure is to alleviate pressure on the health care system" by reducing the spread of the disease, especially in the more vulnerable group. But, they wrote, "if health care absenteeism is high, the system's capacity could be reduced when the virus is most prevalent and the demand for health care services is high."

The report asserts that the cost from work absenteeism is based on conservative lost wages figures rather than broader compensation. The analysis doesn't take into account the loss of fringe benefits, subsequent lost income if an absent worker is fired, and additional financial strains on families that are otherwise borne by schools—such as free lunch programs.

Beyond the financial impacts, there would also be difficult-to-quantify lags in learning, especially in the case of longer school closures. Unlike the case during summer breaks, there are usually no enrichment programs in place in the winter to keep children up to speed on their studies and other skills. And any group activities or care would negate the benefit of the controversial closings, as Epstein pointed out in the press briefing: "If you close schools and all the kids go to the mall and mix there, you really didn't reduce the amount of transmission."

Despite the difficulties—both logistical and financial—of dismissing classes, the report authors do not dismiss it as a potentially beneficial strategy should the need arise. "If the epidemic is severe the benefits of closing schools may well outweigh the costs," Epstein said.