Hello everyone, I'm Abby Carlson.
I'm an infectious diseases physician and a doctor here
at the Centers for Disease Control and Prevention in Atlanta, Georgia.
And today, we're going to talk about a topic that you hear about a lot,
respiratory droplets and how they spread COVID-19.
Okay, we know that we want to keep from getting infected with the virus SARS-CoV-2,
so that we don't get sick with the disease COVID-19.
But how does the virus get from one person to another?
The answer is actually different for every virus,
but for SARS-CoV-2, the main way that the virus seems to travel between people
is through something called respiratory droplets,
but, what are those?
In this case, "droplet" doesn't just mean a water that you can see,
like big raindrops or splashes in the sink or a pool.
These droplets we're talking about are actually really tiny,
and where they come from might surprise you.
You might think that when you breathe out, all that comes out is air, right?
You don't see anything else.
But in fact, our breath contains a lot of water,
and usually you can't see that water.
But think about it for just a moment.
When you go outside in cold weather and you breathe out, you see your breath,
or if you breathe on a mirror it fogs up,
or, this one actually happens to me all the time.
When I'm in the hospital, I put on my mask, and my glasses start fogging up.
What you're seeing in all these cases is not air.
It's all the water in your breath.
Those are your respiratory droplets.
So, every time that we let out air when we breathe,
whether we're talking, or singing, or just sitting here breathing,
we also let out those little, tiny respiratory droplets.
I'll pause here for a moment and say that although all of these droplets are small,
they aren't all the same size of small.
Some you can actually see, like when you sneeze.
Most of them, though, are sizes that we can't see,
and different-sized droplets can travel different distances in the air.
Some will go farther than others.
The distance they travel also depends on other things like the air currents in the room
or how strongly they were pushed out, like when you cough.
We'll talk about these ideas more in another episode later on,
because this difference in sizes is very important
for certain things we do in infection control.
For now, though, it's important to know that
even though these droplets come in a lot of different sizes,
they're all small enough and light enough that if another person is close by,
and we aren't wearing our masks -- say, we're eating at a table
or we're with a patient who doesn't have a mask on either,
then, that person can breathe in the droplets that we've just breathed out.
And when someone is infected with SARS-CoV-2,
those tiny respiratory droplets have virus particles inside of them.
If you breathe in respiratory droplets, they're carrying that virus
that can then get onto your nose and into your throat and your lungs.
It sounds really gross, I know, but that's what happens.
And they can also land on your eyes.
And when those droplets land in all of those places, the virus lands on cells.
Some cells they can't get into, they just don't have the way in.
but like many other respiratory viruses,
SARS-CoV-2 is able to get into a lot of cells in our nose, our throat, our eyes, and our lungs,
and when that happens, the virus can then hijack the cells.
And that's how we get sick with COVID-19.
We'll talk more about how, exactly, viruses hijack cells in another episode.
So be sure to stay tuned for that.
Now, if the goal of infection control is to keep people from getting sick,
and we know that respiratory droplets are the main way SARS-CoV-2 moves between people,
then we know that the actions that we take for infection control
and that we need in healthcare settings
are things to keep people -- ourselves and our patients --
from breathing in each other's respiratory droplets.
I know there are already a lot more questions about this topic.
We've covered respiratory droplets very quickly today,
and we'll talk more about them in future episodes because there's a lot to cover.
For the meantime, thank you all for joining us.
As always, be sure to follow up on Facebook or Twitter
and check us out on our website at CDC.gov/ProjectFirstline
We'll see you back for the next episode.