People seem to be talking about COVID-19 all the time now… but do you understand how it works, and how it is similar to other viruses and how it’s different? Here’s my summary of the parts that a prepper should know. I’m no a physician, but I am a pathophysiologist who’s been reading a lot pushed out by the people who know best.
How’d this COVID-19 thing happen anyway?
If you’re a longtime reader, you’ll be aware that a pandemic virus has been at the top of my list of risks for a serious disruption. Here’s why: You’ve got a bunch of viruses running around in animals. Each animal species has its own kinds of viruses. The animals are infected, but usually don’t get symptoms; or don’t get serious symptoms. The host and the virus or adapted to each other. It’s like humans with cold viruses.
But you’ve got that species and its viruses living in close association with humans. So eventually one of the viruses in one of the members of the other species gets a mutation that allows it to transfer easily to humans and also transfer between humans. Now you have what’s called a zoonotic disease (because it came from it was passed over from a different animal).
(Yes, COVID-19 did jump from bats to humans. But if you’re an American sharpening up your ‘bat-eaters’ jokes, keep in mind that the American habit of eating pigs was almost certainly responsible for the ‘Spanish’ flu epidemic of 1918.)
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Why doesn’t our immune system protect us from COVID-19?
The virus and the new human host are not adapted to each other. Now the virus causes a much uglier situation because the immune system of the human has never been exposed to this before. We do have a small number of white blood cells that will be able to attack it because we make some white blood cells for almost any contingency. But since there are so, so many options, you don’t have very many cells that can react to any one unknown target.
So there is an immune response; but it’s slow to get effective. During that delay, the virus can reproduce itself enough to cause very serious, and sometimes fatal, outcomes.
What it means that COVID-19 is a virus?
What’s it mean to be a virus? COVID-19 isn’t a living thing, really. It’s a protein coat with the few genes it needs to trick a host cell into making more viruses. And it’s got a little lipid (fat) envelope around the outside.
Why’s that relevant? Well, for one thing, it means antibiotics don’t work against it. They are used for treatment with COVID-19 infections, but only to stop bacteria from invading already-damaged lungs and adding more problems.
So how does a not-live thing reproduce? COVID-19 has little proteins on it that latch on to proteins on the surfaces of our cells. The virus injects It’s genes into our cells. These genes , program our cells to make more viruses. The host cells, which line the respiratory tract mostly, die from making and releases new viruses. That causes respiratory problems.
A coronavirus attaching to respiratory tract cell…Invasion.
Once the immune system does get geared up, it can help. Or, make things worse. What? In many cases (80% or more), it gears up Enough, and the person recovers. In a few cases, usually after the virus itself has done a number on the lungs, the immune system gets Too worked up and causes additional damage. (This is a cytokine storm, but not of the worst sort. It doesn’t hit early and it doesn’t mostly hit those who are otherwise most fit.)
How does a COVID-19 infection progress?
There’ll be a period of usually 3 to 14 days where that virus is replicating itself and the immune system has noticed a little bit and it started to build itself up. There is no real symptoms yet because the response is not strong enough. After this incubation period, the subject will usually start showing some symptoms. They’ll most often get a little bit of dry cough and a fever. (Other symptoms are possible, but let’s stick to the main story.)
In about 80% of people who show symptoms, the immune system will get rid of it before it gets really serious. In the other 20% the virus will keep replicating, and it’ll start to infect the lower airways down in the lungs more. It will start causing a lot of inflammation in the lungs. The lungs will be damaged (giving the characteristic x-ray).
About 15% of the people who show any symptoms at all from this thing will end up needing to go to a hospital with it and get at least oxygen supplied by nasal cannula. And about 5% of the people who develop symptoms will end up getting such serious outcomes that they need to go into intensive care. And some of those people need to be put on ventilators at that point.
This is a pretty ugly situation because only about 12% of the people who go on ventilators with COVID-19 are ever coming off of them alive.
What’s the difference between someone being “positive” and being a “case” of COVID-19?
Infections of COVID-19 don’t necessarily become “cases”. You’re not a “case” of COVID-19 unless you both have it and get symptoms from it.
We think that some subset of people who get it never show symptoms (Way to go, immune systems!). How many? There’s a hypothesis out there that it’s a lot; but frankly I’m not convinced. Why not? No real evidence. The only way to know is to test the person after they’ve been several weeks without symptoms to see if they have made antibodies to the virus, and nobody has done that.
When people who tested positive without symptoms Have been followed for long enough to be sure…most of them have gotten symptoms and become “cases” eventually. It’s still early days yet though, and good numbers aren’t available.
Also, the hypothesis that the virus has been running around without causing much illness for more than a month has a big problem. It doesn’t explain why we most definitely are seeing a bunch of people who need to be put on respirators all of a sudden. A little cough overlooked, sure, plausible. But a bunch of people with a little cough getting overlooked and Then suddenly thousands of people need ventilators in one week? I don’t think so.
So it’s possible that a lot of people never do develop symptoms if exposed…but people who claim it as a truth are engaging in wishful thinking at this point. So far as I can tell from available data.
How COVID-19 is different; and how it’s not
COVID-19 is mostly transmitted by respiration droplets like influenza. It’s similar to flus in that touching a contaminated surface then touching mucus membranes or food is a popular transmission route. But COVID-19 is better at transmitting in little air droplets. So somebody who’s standing five feet from you is talking to you. You don’t notice that tiny little droplets of their body fluids or coming your way, but they are, and you can pick them up by inhaling
COVID-19 not as dangerous as SARS on a case by case basis. SARS is the most closely related virus most people are aware of. COVID-19 is in the same family as the SARS virus that caused an epidemic a few years ago; but the SARS epidemic was handled much more effectively in the early stages. Every single person who was exposed to SARS was tracked down and watched, and a lot of them were put under isolation for a couple of weeks.
SARS did not transmit in the asymptomatic form, So once people started showing any signs and symptoms, so this aggressive isolation of sick people was very effective. We got SARS stamped out this way, but COVID-19 transmits while it’s asymptomatic. COVID is out, and we aren’t even pretending to try and follow cases and transmissions anymore, which is the effective way to stop it. So, honestly, we’ve got no really good tool for stopping this. Social isolation can slow it, but it generally can’t stop it without the case tracking. And that’s probably never gonna happen because there are too many cases out there to do it.
So we’re using shows social distancing to keep the spread slow enough to give us time to get vaccines, and especially to give us time to not overwhelm the health care system with that 5% of people who need intensive care to try. And we’re trying keep it away from the people who are most vulnerable and to give us time to figure out how to treat it most effectively. That’s where we are as we do this piece at the end of March 2020.