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Scientists now know why some people spread viruses more easily than others – the physiology of a superspreader.


Flus and viruses like COVID-19, spread by jumping from person to person. Some people spread viruses more easily than others. In fact, the majority of virus infections come from a very small group of people. The people that most easily spread viruses are called “superspreaders”. Now scientists have identified the features that make some people superspreaders.

Scientists study superspreaders

It’s tempting to label superspreaders as the people who don’t cover their mouth when they cough. However, scientists have found that there is much more to it than a person’s behavior. Their physiology impacts how easily they spread viruses.

Scientists used research studies and computer models of the human head to figure out why some people spread viruses easier than others. They found viruses spread easier when sneeze droplets travel farther and linger longer in the air. They next studied how the shape and form of a person’s head and face could cause droplets to spray further and hang around longer in the air.

How congestion contributes to virus spreading

Scientists discovered that congestion in the nose and sinuses alters the way nose droplets eject from the nose. For instance, people with congested noses restrict the area that the sneeze can exit from. This causes sneeze droplets expelled from the mouth to increase in velocity and thus, travel further. When people have a clear nose, like after blowing it into a tissue, the speed and distance sneeze droplets travel decrease.

How teeth impact a sneeze’s spread

Teeth also restrict the sneeze’s exit and cause droplets to travel faster. Teeth create a narrowing effect in the jet that makes it stronger and more turbulent. A person with a full set of teeth ejects sneeze droplets about 60% further than those with less or smaller teeth.

How saliva and mucus thickness allow sneeze droplets to linger

The thickness of saliva also comes into play. Thinner saliva results in smaller droplets. These smaller droplets create a mist-like spray that stays in the air longer. Sneezes with thicker saliva drop quickly to the ground where they cannot be inhaled by another person.

Don’t be a superspreader

Together, these findings hint at how we can help stem the spread of viruses. Cough drops can thicken the saliva and reduce the misting effect of a sneeze. Blowing your nose keeps the sinuses clear which reduces the distance sneeze droplets travel. And of course, cover your mouth when you cough or sneeze.

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