Even with the flu being widespread across the country, it's still not one for the record books -- at least not yet. It's classified as moderately severe.

In Colorado, state health officials report the virus has hospitalized more than 2,000 people as of Jan. 17.

Here's the thing, the flu isn't only impacting people's health. There a chance it could have a big effect on businesses' bottom line. We're talking billions of dollars.

Challenger, Gray and Christmas, Inc. is a national business consulting firm. It's forecasting American employers will lose around $9.4 billion in the next two months. The reason? With the way things are going, there's a likely chance bosses will have to pay employees who are at home sick and not at the office working.

Staying home sick isn't a problem, but showing up to work ill most certainly is. So a word of advice from the consulting firm: don't be afraid to call in sick.

"Oftentimes, there's this overwhelming feeling that there's too much work to be done and you can't take a couple days off," Andrew Challenger, vice president of global outplacement consultancy, said. "But really, if you go into the office sick, you end up causing more losses for the company in terms of other people that are going to have to miss work."

Are you curious how the firm arrived at their calculation? You can click here to learn how they got that big number.

If you want to know what you can do to stay healthy at work, 9NEWS medical expert Dr. Comilla Sasson explains in the video above.