Great news: The unemployment rate in the United States was 3.5 percent in December, representing a historic low. 

Not-so-great news: We're on track for a historic flu season. There have been 9.7 million cases as of the beginning of January (with five more months to go).

Now, a study led by three U.S. economists suggests the two trends may be related. 

For every 1 percent improvement in the employment rate, the researchers found, we get a 16 percent jump in the number of flu-related physician visits.

The rate correlates highest in the retail and health care industries, which are the industries that have the highest levels of human contact.

Let's talk about the flu

Disclosure: I have the flu as I write this, and it is no joke.

Aches, chills, fever, cough, and lethargy like I can't even tell you. I must have slept nearly 20 hours out of the past 24. 

In fact, as soon as I finish this article, it's back to bed.

I got my flu shot, and I got to the doctor and went on oseltamivir (also known as Tamiflu) quickly, and I'm generally a healthy person. 

So, basically, if you're going to get the flu, I'm probably in about the best situation to get it.

But, still, it's no fun. And you should do everything you can to keep yourself -- and your employees -- from getting it.

The modern workplace

As the economists wrote in an earlier working paper version of their article, the flu is transmitted when healthy people either touch surfaces that have the virus on them or inhale it when an infected person coughs or sneezes.

That means that the modern workplace is almost tailor-made for transmission. Among the factors:

  • Commuting via public transportation 
  • Working in climate-controlled indoor offices
  • Sharing workspaces
  • Placing young children in daycare

"If the features of the working environment promote the spread of the flu, then being out of the labor force and away from these environments could help reduce the spread of the flu," they wrote.

The study, by professors Sara Markowitz of Emory University, Erik T. Nesson of Ball State University, and Joshua Robinson of the University of Alabama at Birmingham, was published in the journal Economics & Human Biology.

What to do

As an employer, you're basically the first line of defense for the rest of us. So here's what you can do:

  • Proactively tell your employees that if they think they may have the flu, they should stay home -- and see a doctor.
  • Similarly, flu or not, ask anyone who gets a fever of more than 100 degrees to stay home for at least 24 hours.
  • Encourage everyone who works for you to get their flu shots. If it's not practical to offer them onsite, offer paid time off for people to go get them.
  • Remind them that it's not too late: The Centers for Disease Control says the peak flu season runs through February and into March, but lasts overall until May.
  • Be especially lenient on remote working policies, especially when you have employees who may have children or other family members who become sick, and need care.
  • On the easiest practical level, make sure there are lots of "tissues, no-touch trash cans, hand soap, and/or hand sanitizer" in your workplace (this via the CDC).

On that last point, some other studies have shown hand sanitizer might not be as effective as hand washing in killing the influenza virus. It's sort of like the chicken soup of remedies: couldn't hurt.

"Since a person may be infectious while experiencing mild symptoms, this greatly increases the probability that the virus will spread to other workers," Nesson told U.S. News. "This implies that firms should consider more generous sick day policies, particularly during the flu season."

Speaking of which, I won't be at work tomorrow. Here's hoping I haven't spread the flu to anyone else.