Tuesday, January 18, 2022

How Coronaviruses attack and why this illustration might not be the best way to think about the virus

The book The Great Influenza was written in 2004 and updated with minor additions in 2005 and 2018. The book concerns itself with the Spanish Flu virus of 1918, but it has great relevance today. It gives a simplified but understandable detail on why coronaviruses (and HIV) are so hard to understand and treat.

This is the Covid virus. But this thing attacks a non-virus cell. That cell looks normal  until hundreds of thousands of newly created Covid cells are ready to burst out of an infected cell.

So let's start with a virus itself. Is a virus alive?

Kind of. Most scientist and biologists consider life to be the ability to eat, shit and reproduce. Even single cell bacteria do these basic processes. But viruses cannot reproduce as we understand it. Viruses attack other cells, taking them over then forcing them to replicate hundreds or thousands or hundreds of thousands copies of themselves. They neither "eat" or "shit" in this system.

This also goes to the way to the body attacks viruses versus bacterial infections. Bacteria designates their makeup through DNA - like nearly all "living" things do. So when a bacteria reproduces, its DNA designates itself as unique. That is why when you get a bacterial infection, antibodies work. Because they help the body strengthen its own immune response to a rouge DNA. But Antibiotics do not work on viruses, in part because there is no DNA strand to identify it. The body can understand bacteria as outside DNA strands being "other" and attack them. 

But viruses enter a internal cell, and so the body doesn't not immediately understand they are foreign. The host cell still identifies to the body - via its DNA - as "internal do not harm". Viruses define themselves with RNA strings. So when a virus attacks a cell from the inside out,the DNA string reads as "part of us" until it bursts open releasing thousands of virus markers that will invade other cells with a now unique marker RNA strand. But since hundreds or thousands or hundreds of thousands of these are released at once, the body cannot usually react fast enough to fight them all. You get sick. The quicker you can fight these virus cells, the more likely you are to survive.

Coronavirus / Covid 19 (Covid 19 is one type of a Coronavirus), releases a TON of these at once, overwhelming the immune system. People who cannot react quickly enough, the elderly and the immunocompromised, can't beat off the infection and die. The common flu does the same thing, but usually releases ewer of these attack cells, and a healthy body can fight them off.

How do we get immunity?

Once the body has been infected and fought the virus, it has a memory now not just of the DNA of the body but the DNA/ RNA marker for the virus and can mount a quicker defense next time. Hence the hope of many people that "natural immunity" will work.

Moderna and Pfizer type of vaccines are not in the The Great Influenza book, because mRNA procedures are so new. But the mRNA vaccine essentially prewarns the body that a certain DNA/RNA marker should be attacked immediately, due to an RNA marker.

Then why do people who have had Covid or the Vaccine get sick with Omicron?

Well, viruses have a unique superpower. They can evolve their RNA coding quickly. Mush MUCH quicker than DNA evolves. Because the virus penetrates a cell and makes hundreds of thousands of copies, often times slightly different RNA sequences come up. If the change is large enough, the new DNA/RNA sequence no longer reads as the same virus, so the body, once again, reads it as part of us.

Since it is close to the original sequences, the body understands this more quickly now and will attack it more quickly. What we see is unvaccinated bodies may have learned how to recognize the attack cells, but they cannot quickly make sense of the new DNA / RNA combinations quick enough to prevent infection. Those vaccinated bodies can much more quickly hunt down not just the DNA / RNA combination, but the RNA can be identified quicker (hence bodies may become positive, but not always nearly as sick).

By the by, this evolution is called antigen drift. Your body may be able to tell if you've had covid through the RNA sequence, but if the RNA drifts enough, your body cannot recognize the new variant as the same disease.

When does it stop?

I don't know. I think that when enough bodies have seen latest RNA message and the virus cannot jump from person to person. Whether through recovery or Vaccines that mimic the virus or through mRNA vaccines. That is when the virus plays out. 

And the anti-vax people are correct that "natural immunity" will ultimately work. But only after a ton of deaths occur with each variant. That not only accepts a lot of death as a result, but at the same time is overwhelming our medical systems.

Now imagine if Omicron hit and NO one was vaccinated against it! If hospitals are overwhelmed when 30% of the population can't defined itself, image in 100% of the population could not.

How about the seasonal flu?

The seasonal flu works the same way, only it replicates in the body a lot slower (think hundreds of attack cells, not hundreds of thousands). Given this slower transmission, the RNA sequence doesn't have enough time to really mute or drift a lot. Our seasonal flu shots try to take into account older flu RNA markers, and maybe some new ones that have been spotted somewhere. But the slow replication means that healthy younger people can usually fight it off natureally.

2 comments:

  1. Nice summary; very understandable. Thanks

    ReplyDelete
  2. Thanx Lynnie. After I reread that part of the book (Chapter 7) I found it a pretty simple explanation.

    ReplyDelete

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