We've known that children get infected with COVID-19 less frequently and have less severe symptoms than adults.
Why? Inside our noses we have ACE2 receptors that bind perfectly with the novel coronavirus, that's how the virus goes into the body. But children don't make ACE2 receptors as frequently as adults do.
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"So the implication is that if there is no door for the disease to get in there, there is no or limited disease in elementary age students and that's why we're seeing that pattern," explained Dr. Naomi Bardach of UCSF's Pediatric Department.
Elementary school kids also have smaller lungs, so when they sneeze or cough they don't spread the particles as far as high school students or adults do.
Another interesting fact is that size does matter. Kids are shorter and their viral particles drop to the floor-which means they can't spread upward toward the adults in the room.
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Perhaps the most important point that UCSF wants to make is that masks, physical distancing and ventilation are key to curbing the spread of the virus.
Take for example a high school in Israel. Dr. Bardach showed reporters a picture of students wearing masks but not sitting apart from each other.
Then, for two days there was a heatwave and every student was allowed to take their masks off.
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"The air conditioning was on, the windows were closed and it led to over 150 people in the school getting infected," added Dr. Bardach.
UCSF researchers now say a mask will protect others as much as it protects you because it can control how much virus actually comes into your body.
"So it's not that you can't get it, it's just that actually the severity of the illness is lower which means anyone including teachers will be less likely to have a bad illness with it," said Dr. Bardach.
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