The sick season is upon us, so why do so many people avoid flu shots?

No one likes needles. Even so, flu shots are like cod liver oil and spinach: Hard to stomach, but very good for you.

Here is  a quick look at the flu by the numbers:

* In a typical year, up to one-fifth of the U.S. population gets hit with the flu.

* On average, about 36,000 people die from it.

* The U.S. government recommends that virtually all 330 million Americans get vaccinated.

Despite new recommendations, only 37% of Americans surveyed by Consumer Reports say they will get the flu shot this year. (Another 31% are undecided.) There are many health risks related to the flu, but here are three financial reasons to get the shot:

When workers are ill, the economy is sick. Sick workers may be good for Kimberly-Clark (tissues), Procter & Gamble (NyQuil), along with CBS (Oprah), but they also hurt productivity. The overall economic impact of the flu in the U.S. is $87.1 billion each year. According to the Center for Prevention and Health Services, the flu indirectly costs your employer about $76.7 million, on average, in missed work and other indirect costs like healthcare.

You don’t want to miss valuable face time. The Department of Labor says the number of workers who miss work due to illness, injury or medical visit spikes during the months of December to March, commonly referred to as “the flu season.” According to one study, workers who fail to get vaccinated accounted for 45% of all days of illness during the period, 39% of all illness-related work days lost and 49% of all days with illness-related reduced on-the-job productivity.

There is no good data on the number of days the average worker misses due to the flu — it varies anywhere from one to 10 days, the CDC says. There are several reasons why it is so hard to quantify time missed from work due to the flu. Workers may stay at home to care for sick children, for example. And the virus affects everyone differently:  “There are people who feel better after two or three days, and there are people who can be really knocked out of the loop and not feel better for five days or more,” explains Andrew Pekosz, associate professor of microbiology and immunology at Johns Hopkins University’s Bloomberg School of Public Health.

Flu shots are often free. Many companies offer free flu shots. According to a National Business Group on Health survey, 79% of employers that have consumer-driven health plans (also known as high-deductible plans) offer free flu shots, while 67% of employers with traditional health insurance benefits offer free flu shots to workers. If your employer doesn’t give shots for free, expect to pay anywhere from $25 to $29 this flu season, the CDC says.

Keep in mind that it takes about two to four weeks for the full immune response of a flu shot to kick in. And while flu season officially begins in December, it’s not too late, Pekosz says. “Any time you get the flu shot is better than not getting the flu shot at all,” he says.

To find a vaccination provider in your area, use this handy flu shot finder.