Every year, like clock work, about 2-3 weeks after school starts, everyone starts getting colds.
The precision of the timing is eerie, the regularity of it repeating is very strangely reliable.
What is going on? Why do the viruses infect all of us so readily whenever the school year starts? Where are they in the summer, what about school gets this going?
Some recent studies open a door to answers, some long known facts also go a long way to explain this phenomenon.
What’s a Cold?
For the most part, the disease we are talking about showing up every start of the school year is the cold.
We say the word cold all the time, but in order to understand why there is such a dramatic connection between school and getting sick, it helps to be reminded of just what is a cold.
A cold is an infection of the airways by a virus.
The word cold got applied to these infections in two ways. The first is that many people who get a cold feel cold. Surely anyone who gets any level of fever will feel cold. But the word also comes to us because more people seem to get these infections, at least where the language English developed, in colder weather, more in school days and not camp days.
But let’s get back to the definition, a cold is an infection of the airways by a virus. We talked about the word cold, what about airway?
The airways are all the parts of the body that touch air as it flows in and out of the lungs. That includes the lining of the following key parts of the body: nose and mouth (where all air enters), throat and windpipes (where all air flows), and lungs (the destination for all incoming air).
So cold is a viral infection of the lining of these structures.
What’s a Virus?
Now to the virus. A virus is a curious, meddlesome, tiny bit of…. ….information. That’s right, it more a tiny bit of information than a form of life. How so? Viruses typically contain only 2 parts: a protein coat, and a package of DNA or RNA inside the coat, that’s it. Left alone, these packages of genes simply sit there and can for a very, very long time. They only do anything when they contact cells that they can pick the lock to and take over.
The way it works is that in order to go into action, the protein coat of the virus must connect to a cell where those viral proteins know how to convince the guards on the surface of the cell to let them in. A human cold virus cannot fool the cells of the skin, or gut, or liver, if they clump around these parts of our body, nothing happens. They also cannot fool the cells of any other animal.
Ah, but let a human cold virus land on the lining of the airway, and voila!!, the virus fools the gates and gets in.
Once in, the protein coat delivers the tiny clump of DNA or RNA (genetic material) to the DNA of the cell. The information in the viral DNA takes over your cell’s DNA and commands it to make a ton of copies of the viral DNA and tons of the viral proteins. Those tons of material assemble into zillions of new viruses, and this typically explodes the cell, and unleashes zillions of new viruses to do the same to the cell next door.
And so a viral infection is a slow burning fuse of destroyed cells.
Typically cold viruses land in the nose first, destroying the lining of the nose, causing a runny nose. Then the fuse burns down the throat causing a sore throat, then the lungs, causing a cough.
The nose is smaller than the throat, which is far smaller than the surface of the lungs, so the runny nose and sore throat usually don’t last as long as the cough.
Back to School
All that is all very well and good, but what’s that have to do with school?
One of the most favorite games played in the office, is guessing who “gave” my child their cold?
It must have been Charlie who was sneezing next to my child in class, or Susie who sneezed at my child during recess.
Charlie and Susie may have been the source, but it turns out at any given moment, dozens, hundreds, thousands of kids and adults are pouring zillions (not millions) of cold virus into the air. Your child’s cold was caused by a virus from one of them, but it is hopeless to know just who for the following reasons.
In 2015, a group of scientists did something incredible, and a bit creepy.
They counted the number of viruses a person breathes in during one day, in various places
What they found was that during one day the typical person will breathe in this number of viruses in each place:
- Outdoors- 1 million
- Indoors- 5 million
- Your home- 5 million
- School room- 5 million
- Day care center- 4 million
- Restaurant- 3.5 million
- Doctor;s office- 2.6 million
(I am especially proud of the fact that our office has about half the number of viruses in the air as at home or school)
Now, good luck finding out which person gave you their zillion viruses, got you sick. Yes, each sneeze has 200 million viruses, but we breathe in about 5 million a day in a classroom, so tracking where those 5 million came from is, sadly, impossible. As noted above, the culprit could be Charlie or Susie, but with 5 million breathed in every day, who can say exactly where each of the 5 million viruses came from, you can’t know.
One more point about school- density and catching.
It turns out that cold viruses are pretty miserable at catching hold in their new host. It takes about 100 hours for a person to breathe in cold virus before the chance they will get sick rises to 50%.
That fact leads to one of my favorite virus facts, although aren’t all these facts amazing? That is, it takes about 6 people in a room to get a cycle of colds really going.
Classrooms are the perfect vehicle to make this fact come alive. They all have more than 6 people in a room, and they are packed in there for hours every day.
So take a class of only 10 people, and have them be in that room about 4 hours a day- that’s about 40 hours of exposure if you add up all 10 people, in 3 days you have crossed the 100 hour mark of exposure to everyone’s viruses in that room.
- Every school year, like clockwork, colds start raging within a week or two of school starting. We are seeing this, for real, in our office. By the end of last week, vast epidemics of colds sprouted up.
- Colds are infections of our airways by viruses.
- Viruses surround us to a vast degree it is hard to imagine, even in our homes we breathe in 5 million viruses every day. In two days, at home, we breathe in more viruses than there are people in Ohio!
- Pack about 6 people in a room for more than a few hours and the viruses really begin to pick up their infection rate- that’s what a school class room does.
So, it is not your imagination. Going to school creates environments where viral epidemics of colds really take off. We see it every year, your family experiences it every year.
Let’s let Charlie and Susie, and for that matter each member of your family, off the hook. We live in a truly vast ocean of virus. Classrooms concentrate that ocean and get the epidemics going, but never mind who gave it to you or your child, let’s just make sure they are comfy while getting better.
And, if you want a break from the sea of virus, come visit Advanced Pediatrics, where the air has half as much virus as most places.
To your health!
Dr. Arthur Lavin