You're standing in a crowded room when all of a sudden, without warning, a person 7 feet away sneezes without covering their mouth. "Bless you," you say politely, while finding comfort in the idea that you're far enough from them to not be affected by their germs. Unfortunately, however, you may not be as safe as you think.

As Gross Science host Anna Rothchild explains, research on germ travel has come a long way since the 1930s, when Harvard scientist William Firth Wells used sneeze powder to make study participants sneeze. Most recently, in 2014, researchers at MIT used high-speed cameras to watch how far droplets from a sneeze spread. They found particles from a person's sneeze could travel further than we'd expect throughout a room, and even get caught in air vents where they linger long after the sneeze.

As if lingering sneeze particles weren't scary enough, researchers in the UK conducted an experiment to find out how far particles from vomit traveled, too. They found they could travel much farther than the human eye can see, with one projectile vomit episode's particles traveling almost 85 square feet, Rothchild said (gross!). What's more, unfortunately, those germs can stay active for days at a time.

So what can you do to protect yourself from the spread of germs? Wash your hands often and, if you're in a crowded room with someone who has a cold, remind them that covering their mouth (and perhaps even using a handkerchief) is both polite and sanitary.