How Far Can Germs Spread From A Sneeze Or A Cough?

01/24/17 By Jill Tilton

Picture this: you are sitting down at your desk at work. You hear a sneeze sneak out from your co-worker a few desks over, followed by an eruption of “bless you’s” and that one guy that yells out “gesundheit.” You suddenly self-examine to see if you feel a small sniffle yourself, check your throat for scratchiness. Do you ever wonder how far the germs from that one sneeze (or a cough) can travel? Stay tuned as we discuss.

Coughs

Each cough is filled with thousands of droplets of saliva. On average, 3,000 droplets are expelled in a single cough, and some of them fly out of the mouth at speeds of up to 50mph. If you have ever been hit by a cough directly in the face (by accident of course), it feels like it is coming at you that fast in the moment!

Coughs start with a deep breath – followed by compression of air in the lungs – and then a crackling burst as that air is forced out in the fraction of a second. To think about it in a more relatable way: the average human cough would fill about three-quarters of a two-liter soda bottle with air — air that shoots out of the lungs in a jet several feet long. Now think about all of the germs that are in that cough!

Sneeze

Surprisingly a sneeze is even worse than a cough! How does that even happen? Well, instead of starting out in the lungs, a sneeze starts at the back of the throat. By starting at the back of the throat, many more droplets are produced, around 40,000 if you were curious. Once a sneeze is produced the droplets fly out at speeds over 200mph! Many of these gross sneeze droplets cannot be seen because they are smaller than the width of a human hair.

How Do These Germs Travel Through A Room?

It is quite easy once the germs of a sneeze or a cough are expelled. The larger droplets will fall to the floor (or onto your desk) while the very small droplets can remain airborne almost indefinitely and be disbursed in the room’s airflow. The larger droplets, once they land, are not permanently in place, however. They can be kicked up again by a door opening and affecting the airflow in a room. A sick person’s cough can contain two hundred million individual virus particles. 

Thinking again about your office environment and the sick person a few cubicles away. The particles from that one cough or sneeze, once airborne, viruses in these tiny droplets can survive for hours. Even if the droplets hit a surface (like their desk), the viruses can survive and still spread disease if the droplets become airborne later. When a droplet lands on paper, its virus particles can survive for hours. On steel or plastic, they can survive for days.

The Cycle Continues

Once these germs reach your desk – land on your keyboard, phone, or notepad, have the risk of infecting you. Once these droplets are breathed in, or taken in by your nail biting habit (which was your new year’s resolution to stop), they will settle in on the cells at the back of your throat where they will attempt to begin replicating. 

Your body’s natural defenses will attempt to eliminate the infection. Some will succeed, and others will fail. If your body cannot totally destroy the virus, your body will deal with the infection by bringing up mucus to help clear it. Some of this mucus is swallowed, carrying the virus down to be destroyed by stomach acid. Some viruses in the throat, though, will be expelled when we cough and this coughing expels the mucus (and new virus) out of the body, and the process starts over again. 

With cold and flu season in full force, be sure to be constantly washing your hands and disinfecting your workspace, especially if your co-worker is coughing or sneezing.

Take preventative action now and download our flu eBook!

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References: 
https://www.livescience.com/3686-gross-science-cough-sneeze.html
https://www.sott.net/article/277306-Germs-from-coughs-and-sneezes-travel-further-than-previously-thought