I’ve been interested in the semantics of what’s happening right now. Everyone is using different terms to refer to things, so I did some research.
When I’m confused, I tend to write things down. What’s below is one result of this.
I’m not a medical professional, but this is what I found out.
It turns out that we’re actually interchanging a lot of definitions. These things are different:
- A category of virus: “Coronavirus”
- This specific virus: “SARS-CoV-2”
- A disease: “COVID-19”
Let’s break this down –
A “coronavirus” is a category of virus that’s been known since at least the late 1960s. It’s so-named because, when viewed under an electron microscope, these viruses have little projections that make it look like a crown (the Spanish word for “crown” is “corona”; next time you see a bottle of Corona beer, look for the crown on the label).
A very important point: a virus is a physical thing. Those little projections aren’t hypothetical or imaginary – they are actual physical features on a tiny physical thing that can be observed.
A virus is a little organism. It infects you by entering your body somehow and attaching to one of your cells, then injecting its genetic material into it.
It’s not magic – there’s a specific physical interaction that takes place between two organisms: the virus and a human cell. They sort of merge, which damages the cell in the process. Then the virus starts replicating, damaging other cells, and then you have problems.
Also important: a virus needs to be inside a host to survive. It’s a small lifeform, and if left out in the world, it will eventually die.
There are at least seven different specific types or strains of coronaviruses. Remember, that’s just a category, so saying “THE coronavirus” is not technically correct. There is not just one coronavirus.
Four strains produce mild disorders that simply appear to be a common cold (you know when you go the doctor and they say, “Well, you don’t have strep, so it’s probably viral…”).
Three strains have produced more severe disorders, that we’ve all heard about – SARS in 2003 (not seen since 2004), MERS in 2012 (still around, just not very infectious), and now the situation we find ourselves in today.
The specific strain that’s causing problems right now is technically “SARS-CoV-2,” which means “Severe Acute Respiratory Syndrome - Coronavirus 2.”
While a virus is a specific thing, a “disease” is a set of observed symptoms. Your body can become host to a virus (meaning, the physical interaction discussed above has occurred), but this might not ever develop into a set of symptoms that constitute a disease.
The moment when you “get a disease” is a little blurry. It’s somewhat based on the level of symptoms that you exhibit.
Consider: if you had a disease but never showed any symptoms, then did you ever really have it? The word “disease” literally means “dis-ease” or “not at ease.” If you’re never “not at ease,” then it can be said that you never had a disease. You may have been infected with something like a virus or a bacteria that is known to cause a set of symptoms or problems, but you never actually progressed that that state.
Remember that we also use the word “disease” to talk about sets of symptoms you can’t catch from someone else. The most common cause of death in the world is “heart disease,” which encompasses a bunch of bad things that might be going on with your circulatory system, but that you can’t contract from interactions with a physical thing (except maybe donuts?).
Also consider HIV and AIDS. Infection with a virus called “HIV” reliably causes a set of problems that became known as “AIDS.” HIV is the virus – it’s a specific, physical organism. AIDS is a set of symptoms that constitute a disease. No one ever actually died of HIV – they died of AIDS, the disease/symptoms caused by it. Lots of people have HIV today, but the problems we call “AIDS” are kept at bay by drugs. These people have a virus, but not a disease.
This is why we often use the phrase “full-blown AIDS,” when we really just mean someone showing the symptoms of AIDS, not just being infected with HIV. For many, HIV was the first time we had to wrap our heads around the difference between having a virus and a disease, and so we differentiated the two states by inventing a phrase which made sense to us.
Which brings us to the final definition: COVID-19 (or just “COVID”), which stands for “Coronavirus Disease 2019.” Put another way: “a set of symptoms identified in 2019 caused by infection by a specific strain of coronavirus.”
The symptoms of COVID-19 are fever, dry cough, shortness of breath, etc. This is because the virus replicates inside the respiratory tract, damaging more and more cells, so the lungs can’t do their job. If someone loses too many cells to the virus, they will die from respiratory failure. Their lungs…break, basically.
Viral infection happens at a specific moment in time (when a virus organism enters a cell) and it’s binary (it happened or it didn’t), but diseases take time to develop and can vary in severity. You can be a host to the virus – remember, it’s a little physical thing – for weeks before your body gets damaged enough to start showing symptoms of disease (you experience “dis-ease”). And if the virus is inside you, then you can pass it on – you can breathe out little virus organisms that will enter someone else.
You might never develop the disease from the virus. But, again, you can pass on the virus. A bunch of us might be walking around with SARS-CoV-2 right now, leaving behind lots of little virus organisms wherever we go, yet never come down with COVID-19, so we’d never even know.
So, there are three different, inter-related things we’re dealing with, that are all being lumped together.
- Coronavirus, a general category of viruses we’ve known about for 50 years
- SARS-CoV-2, a specific coronavirus strain first identified in late 2019 that’s become a problem right now
- COVID-19, a set of potentially deadly problems that are sometimes caused from infection by SARS-CoV-2
And this might be completely pedantic, but no one technically dies of “corona.” They die of COVID-19, which is a set of potentially deadly problems that SARS-CoV-2 causes.
Saying someone died of “corona” is like saying someone died of “injury.” Well, sure, but it’s more specific to say they died from being shot by a gun, or from acute blood loss.
There are two others words getting thrown around a lot too: “epidemic” and “pandemic.” They both refer to disease inflicted on a group of people (in Greek, epidemic literally means “upon people”). However, an epidemic just means a disease incidence above what’s normally expected. A pandemic normally refers to geographic spread. A pandemic is something that has spread widely (“pan” means “all” in Greek).
Pandemics have happened all throughout history. The Plague (or “The Black Death”) (the 1300s) was a pandemic, and so was The Spanish Flu (1918-1920). Right now, we have two: AIDs, since the 1980s; and COVID-19, happening right now.
In the end, knowing this doesn’t change anything. But I found it interesting, and maybe you will too.