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Coronavirus: how viruses attack the body and how it fights back

Last Updated Apr 8, 2020 at 10:48 pm EDT

When viruses attack your body, your body fights back — it’s an age old dance and it’s usually standard operating procedure for the body’s immune system.

However, the novel coronavirus that we’ve come to know as COVID-19 has been described as particularly clever in the way it goes about its business of making you ill.

Medical animator David Bolinsky explains the process of how viruses work with an animated video.

How you get infected

When a person coughs or sneezes, they emit several droplets – which is the main way coronavirus is transmitted.

If the person has the virus, the droplets contain hundreds of thousands of those viral particles which then float around in the air. If you breathe one of them in, the virus almost immediately begins to attack the body.

“This is something viruses have been doing as long as there have been cells, for billions of years, and they’re really really good at it,” says Bolinsky

How a virus works in the body

It all starts with a single cell.

Once the virus has entered the body, the “spikes” or small protrusions seen on the outer rim act as keys, allowing them to unlock the door and enter a healthy human cell.

“The cell thinks it’s importing something it might need, nutritionally,” explains Bolinsky, like water or glucose. But what it’s bringing is the opposite of useful.

“The virus has exploited the process. They’re basically the guy who knocks on the door and says ‘pizza delivery’ and it’s the land shark,” he says, referencing the classic Saturday Night Live sketch.

Now that it’s through the door, the virus is quickly able to instruct the cell’s nucleus — which essentially controls what the cell does — to make new viral particles.

So the cell gets tricked into making tens of thousands, hundreds of thousands of proteins it can’t use itself, but the virus can use to self-assemble into new viral particles,” explains Bolinsky.

As new viral particles emerge, they can start infecting more and more cells in the body. This is no small process and each virus particle can replicate into millions more.

How COVID-19 is different

The virus that causes COVID-19 has been described as particularly diabolical when compared to other coronaviruses.

This particular novel coronavirus has a number of different proteins that haven’t been seen before.

For example, the common cold virus will only attach to receptors in the nose and throat area. As such, any infection it causes stays in the upper airways and causes more discomfort than any real damage.

But COVID-19 is far more ambitious.

“The COVID-19 virus attaches to receptors in upper airways, but also attaches to similar receptors deep in the lung,” says Bolinsky, which can lead to serious consequences including respiratory failure.

How the body fights back

“It’s an amazing process,” says Bolinsky.

The body’s plasma cells create antibodies — the cavalry that’s brought in to clean up the mess.

Antibodies act as markers — they attach themselves to the virus particles and make it easy for other cells to identify the invader. They essentially indicate to other cells “this is what you need to go find and kill in order to stop this infection.”

“T-cells which are the soldiers of the immune system, will identify this antibody, attach to a virus and zap it,” explains Bolinsky.

How to avoid infection

“The whole issue here is how do you keep virus particles I’m making from infecting you?” says Bolinsky. “And the only way to do that is to make it impossible for my virus to jump to you, and that’s the easiest thing we can do.”

This means staying home as much as possible, obeying physical distancing orders by staying 6 feet away from other people, washing your hands frequently, not touching your face and self-isolating for 14 days after travel.

In addition, new recommendations from Chief Public Health Officer Theresa Tam say non-medical masks can be worn by the general public as a means of protecting others, even if you are not showing symptoms. There is no scientific evidence to suggest the masks prevent you from catching the virus.

However, a majority of health experts agree that simply not interacting with others is your best defense against COVID-19.

“All the science in the world and all the new inventions in the world and all the medicine in the world isn’t as strong as me staying away from you getting my viruses,” says Bolinsky.

For more on how to avoid infection click here: How to protect yourself and others from infection as COVID-19 cases increase.