Maybe you prepare food for a living. Maybe you feel awfully nauseated. Maybe you clock in, anyway — rent is due in two weeks.

Working Americans often power through illness, advocates say, because the United States doesn’t guarantee paid sick leave. Four in 10 private-sector employees can't take a day off without losing income, according to government data.

Research from the Swiss Economic Institute’s Stefan Pichler and Cornell University’s Nicolas Ziebarth, published this week, explores what happens when paid sick leave becomes a right. They looked at data from Google Flu Trends and the Centers for Disease Control and Prevention from 2003 to 2015 and found that, after U.S. cities mandated the benefit — including San Francisco and the nation’s capital — flu rates dropped an average of 5 percent.

Since roughly half of workers in each city already received paid sick days from their employer, Pichler and Ziebarth concluded that the total impact of compensated time off on area flu rates was likely closer to a 10 percent decrease.

"When workers lack access to paid sick leave," they wrote, "they may go to work despite being sick." More than half of U.S. and Canadian fast food workers in a 2015 survey said they reported to work under the weather because they didn't want to lose money.

The researchers also looked at German labor data to see whether employees with paid sick days used them to play hooky and concluded that, yes, that probably happens. They didn't have the evidence, however, to quantify the frequency.

If you bring your bug to the office, chances are, it'll spread. The American Public Health Association reports that, during the 2009 H1NI outbreak, an estimated 7 million people were infected and 1,500 died because contagious employees didn’t stay in bed.

Many companies offer fully compensated days off to ailing workers — 88 percent of private-sector managers and financial workers receive them, for example — but a hefty chunk of workers at the bottom of the economic ladder must sacrifice income when they catch the flu. About 60 percent of service employees, a customer-facing group, and 38 percent of construction workers would have to give up money to stay home and recover.

Americans, regardless of political ideology, generally support the push to expand the country's paid sick leave. They say extending the option to everyone would better serve public health. Opponents of the benefit, however, say a sweeping mandate could compel employers to lower wages. They'd rather back an optional social insurance program.

Over the past decade, local policies have popped up across the country, requiring primarily large employers to offer a handful of paid days off to mostly full-time workers.

San Francisco was the first U.S. city to protect paid sick days, in 2007, followed by Washington, D.C. (2008), Seattle (2012), Portland and New York (both 2014) and Philadelphia (2015). Connecticut, Massachusetts and California also offer various levels of sick-leave coverage. Oregon introduced the benefit this year.

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