When you’re not feeling 100%, it is written all over your face. At least according to a recently published study it is.

According to Science Mag, researchers concluded that sick people share facial features. Pale skin, swollen faces, droopy eyelids and looking tired reveal that people are not only sick, but may also be contagious.

While the above listed signs may appear to be obvious to most of us, there has been no explicit test conducted on them until now.

To execute the study, researchers collected mug shots of 16 Caucasian volunteers after injecting them with a placebo or a piece of bacteria that made them feel ill. Those who were injected with the bacteria appeared to have an infection, and their immune system responded accordingly.

The researchers ten showed the images to 62 people who were asked to rate their faces as “sick” or “healthy” in five seconds or less.

The results? Participants identified 81 percent of sick people.

In order to find out what exactly led to this simple identification, the researchers had a separate group of 60 people assess how sick and tired the people in the images looked, as well as the extent to which each trait publicized illness.

The conclusion was that pale skin and hanging eyelids were the most accurate predictors of sickness.

Now you have science to confirm who you should avoid for a few days.