It doesn’t pay to work sick.

In fact, one under-the-weather Chipotle worker has been found responsible for costing the company $1 billion over five days for spreading the norovirus that sickened more than 130 customers at a suburban Washington D.C. store.

This is the symptom of a much larger problem. About 69% of hotel and food service workers don’t get paid time off, according to the Bureau of Labor Statistics, so many are inclined to work through being sick rather than lose money. And 26% of U.S. workers have still clocked in while they were ill, because a quarter of them (25%) say their boss expects them to come in no matter what.

So that sets up many employees who come in direct contact with customers – like handling food, serving drinks, working registers and driving cabs –  to power through whatever ails them, which can expose consumers and coworkers to whatever nasty bug is bringing them down.

“Sickness in food service and in the office spreads like wildfire,” Dr. Albert Ahn, clinical instructor of internal medicine at NYU Langone Health, told Moneyish. Disease are spread through direct contact, like handling someone’s food or shaking someone’s hand, or through indirect contact on doorknobs, telephones and office furniture. The norovirus that sickened those Chipotle customers can live on surfaces for weeks. And considering shared workspaces like Regus and WeWork are starting to pick up, with 7,000 users and counting across the globe, the potential to spread disease is spreading, too.

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“For your own sake, you’ll recover more quickly if you stay home and rest,” noted Dr. Ahn, “but you also risk getting your coworkers and everyone you come into contact with sick.”

Dr. Ahn suggests asking yourself these questions to see whether you’re too contagious to work:

  • Do you have a fever?
  • Are you coughing up phlegm, blowing your runny nose constantly, or secreting other contagious bodily fluids?
  • Are you vomiting or do you have diarrhea?
  • Are you functioning so poorly that you’re dragging yourself into work?

Saying yes to any of these implies you have a contagious infection, or that you’re too laid up to be productive. A headache, stuffy nose or menstrual cramps, while uncomfortable, won’t necessarily put you out of commission.

Working while sick – especially in food service – can cost more than your own health. (Fertnig/iStock)

“Secretions are ways to transmit your illness to other people – and they’re all signs that you really should be staying home,” said Dr. Ahn. “Especially if you’re in food service, or working with vulnerable populations in the healthcare industry – like the elderly, young children or people whose immune systems have been compromised – you should not go anywhere near them if you’re sick.”

Plus, workers performing at less than full productivity because of illness costs employers about $160 billion per year, or $218 billion after adjusting for inflation, according to the American Productivity Audit, which is twice as much as the cost of absenteeism due to illness.

But you don’t want to abuse your right to R&R. And almost 1 in 4 U.S. adults have lost a job, or been threatened with being fired, for taking too much sick time.

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“You can be too sick to work, but not sick enough to go to the doctor – but managers can often tell when you’re abusing the absenteeism policy,” Lenny Sanicola, a human resources expert from WorldatWork, told Moneyish.

Here are some signs that Sanicola says managers see as crying wolf when you’re calling out:

  • You’ve already called out sick four times this month; without a doctor’s note.
  • You always call out on Mondays or Fridays, which extends your weekend.
  • You take sick days when work is busiest, like just before a deadline, or during high-traffic weekend shifts.

When you do need to call out, notify your boss as soon as possible so that she can find coverage fast. Give a detailed explanation of what’s wrong (“I have a fever” versus “I feel like crap”). You’ll also look better if you can arrange your own coverage, like a coworker to take your shift, or rescheduling your meetings so that your supervisor doesn’t have to worry about it.

And if you’re considering working through your illness because you need the money, Sanicola suggests telling your manager upfront that you’re willing to work overtime next week, or pick up an extra shift over the weekend.

The bottom line is, you know whether you should stay in bed.

“Having sick people come in can be more costly on the company end than time lost on sick leave,” said Dr. Ahn. “It’s better for everyone in the long run to stay home – not just for your own recovery, but for the company and your customers, too.”