New York (CNNMoney) — An estimated 41.7 million workers can not take sick days -- that's nearly a third of the nation's employees and a problem that raises health risks on everyone.
The nation's current flu epidemic is more widespread in part because millions of sick people trudge to work since they can't afford to stay home.
A study published last year in the American Journal of Public Health estimates that an additional 5 million people became infected with flu symptoms in 2009 alone due to workplace policies, such as lack of paid sick leave.
Most employees with full-time jobs get paid sick days, while only a fraction of part-time workers get them, according to the Bureau of Labor Statistics. The estimates don't include the millions of workers who are self-employed, for whom staying home can often mean being out of business for the day.
While providing sick days may seem expensive for employers, not giving them is also costly. The Centers for Disease Control estimates that even a typical flu season costs businesses about $10.4 billion in direct costs for hospitalizations and outpatient visits for adults. And that doesn't even include the cost of lost productivity and sales.
Another problem: Sick children whose parents can't stay home with them are more likely to be sent to school or day care, spreading the infection to other children, according to Heather Boushey, senior economist at the Center for American Progress, a liberal think tank.
And many sick employees can spread a flu virus to customers and other members of the public. Boushey said about 80% of food-service workers don't have paid sick days. The BLS statisics show even 23% of workers in the healthcare and social assistance sector are without access to paid sick days.
Boushey said the United States is the only developed country without a law guaranteeing employees the right to paid sick days. She said even most undeveloped countries have laws that guarantee paid sick days.
"The U.S. is very much an outlier," she said.