viral replication primer
You've heard of DNA, the genetic code inside each cell that is used to replicate proteins, the genetic code that we pass down to our children via the sexual combination of female egg and male sperm. RNA is a simpler version of DNA that can also replicate proteins, but with a much higher error rate. RNA lacks the ability to proofread the replication process, whereas DNA has a proofreading function. Think of the "D" in DNA as standing for "Double-checking NA", although that's not what it really stands for. Think of the "R" in RNA as standing for "Reckless NA".
With DNA's double-checking proofreading function, it makes replication errors in one step per 100,000,000 on average.
RNA makes replication errors in one step per 10,000 on average. That's 10,000x as often as DNA's error rate.
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The COVID virus variants use RNA to copy themselves after they've successfully infected a human cell. Creating a new copy of a COVID virus requires about 10,000 replication steps. As RNA makes mistakes in one step per 10,000 on average, the average new copy of a COVID virus contains a mistake. On average, each COVID virus that is produced looks slightly different from the previous one.
In other words, most COVID virus particles contain mutations. In the universe of RNA viruses, mutations are the rule not the exception.
As a result, most COVID virus particles don't work. This is typically true for viruses in general -- most virus particles don't work. They're born broken, unable to infect new cells, destined to disappear rather quickly as they erode under environmental pressures (heat, light, hungry neighboring cells, etc.).
This is why a single virus particle is unlikely to cause an infection. To get infected, you need to be exposed to a large number of virus particles. Sometimes dozens, sometimes hundreds, sometimes thousands. When your coworker sneezes on you, the vast majority of those virus particles ejected from her mouth and nose are duds.
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Although viruses are mutating all the fuckin' time, the vast majority of these mutations produce broken copies that don't work. A small fraction of these mutations don't affect the functioning of the virus -- think of them as different color paint jobs -- a purple virus instead of a green virus -- virus particles that otherwise work exactly the same as their parent. An even smaller fraction of these mutations somehow improve the functioning of the virus.
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With respect to the Original COVID-19 that emerged from China, there are countless variants that work pretty much the same as the original -- they differ only with respect to their "color".
Each person who is infected with COVID-19 carries around 10,000,000,000 functioning virus particles at peak infection, on average. Each of these functioning virus particles creates thousands of copies of itself before its host cell bursts, releasing these new copies into the body. Most of these copies are broken, but enough of them work well enough to infect more cells, using those cells to create thousands of copies until they burst, etc. Without our immune systems, COVID-19 would kill us every time, bursting and infecting and bursting its way through our body until we're dead.
Currently, on any given day, tens of millions of humans around the world are actively infected with COVID-19. This means the active population of COVID-19 virus particles at this moment is somewhere around a quintillion, and each of these virus particles is in the midst of creating thousands of copies of itself.
This huge population of virus particles, making mostly mistaken copies of themselves, is bound by the laws of statistics to come up with some random mistakes that actually work better than their parent virus particles.
This has now happened at least three times.
Once in the UK by September 2020, once in South Africa by December 2020, and once in Brazil by January 2021. These three variants of COVID are each some combination of more infectious and less susceptible to antibodies/vaccines than the original China variant discovered in December 2019, and they've each gone global thanks to continued air travel.
You could call the UK variant COVID-20a, the South African variant COVID-20b, and the Brazilian variant COVID-21a.
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Scientists are working to figure out how much more infectious and how less susceptible to antibodies/vaccines these new COVID variants might be.
In general, they seem to be 50% more infectious, and 50% less susceptible to antibodies/vaccines. But we do not know precisely yet.
We know that some people who have already been infected with COVID-19 have been reinfected with one of these three variants.
We know that the vaccines we've already approved are less effective against some of these variants.
As a result, the vaccine manufacturers are already working to update their vaccines to match these variants.
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Meanwhile, a quintillion COVID particles are busily making thousands of copies of themselves at this moment, and most of these copies will be mutations. Most of these mutations will not work. Some of them will work just the same as their parent, but with a different "color" coat. Occasionally, one of them will work better than their parent, and a new variant will have emerged. Maybe the next new variant will appear in the US, maybe in India, maybe in Sweden, maybe in Mexico. Who knows, the process is entirely random. But there's no reason to think we're done with COVID mutations after three new global variants have emerged in a matter of months.
This is why COVID is not going away anytime soon. This is why even if you've had COVID before, or even if you've been vaccinated, you may get COVID again. This is why we're probably going to need annual booster shots for COVID like we do for influenza. This is why I wonder whether we'll ever go back to the old normal, or whether we'll just get used to some average number of daily deaths from COVID, like we're used to an average of 100 daily deaths from influenza in the US.
The chances are you'll get COVID someday, or you'll get COVID again someday. So what will our new normal look like? And for how long will you remain in Quarantine?
With DNA's double-checking proofreading function, it makes replication errors in one step per 100,000,000 on average.
RNA makes replication errors in one step per 10,000 on average. That's 10,000x as often as DNA's error rate.
-----
The COVID virus variants use RNA to copy themselves after they've successfully infected a human cell. Creating a new copy of a COVID virus requires about 10,000 replication steps. As RNA makes mistakes in one step per 10,000 on average, the average new copy of a COVID virus contains a mistake. On average, each COVID virus that is produced looks slightly different from the previous one.
In other words, most COVID virus particles contain mutations. In the universe of RNA viruses, mutations are the rule not the exception.
As a result, most COVID virus particles don't work. This is typically true for viruses in general -- most virus particles don't work. They're born broken, unable to infect new cells, destined to disappear rather quickly as they erode under environmental pressures (heat, light, hungry neighboring cells, etc.).
This is why a single virus particle is unlikely to cause an infection. To get infected, you need to be exposed to a large number of virus particles. Sometimes dozens, sometimes hundreds, sometimes thousands. When your coworker sneezes on you, the vast majority of those virus particles ejected from her mouth and nose are duds.
-----
Although viruses are mutating all the fuckin' time, the vast majority of these mutations produce broken copies that don't work. A small fraction of these mutations don't affect the functioning of the virus -- think of them as different color paint jobs -- a purple virus instead of a green virus -- virus particles that otherwise work exactly the same as their parent. An even smaller fraction of these mutations somehow improve the functioning of the virus.
-----
With respect to the Original COVID-19 that emerged from China, there are countless variants that work pretty much the same as the original -- they differ only with respect to their "color".
Each person who is infected with COVID-19 carries around 10,000,000,000 functioning virus particles at peak infection, on average. Each of these functioning virus particles creates thousands of copies of itself before its host cell bursts, releasing these new copies into the body. Most of these copies are broken, but enough of them work well enough to infect more cells, using those cells to create thousands of copies until they burst, etc. Without our immune systems, COVID-19 would kill us every time, bursting and infecting and bursting its way through our body until we're dead.
Currently, on any given day, tens of millions of humans around the world are actively infected with COVID-19. This means the active population of COVID-19 virus particles at this moment is somewhere around a quintillion, and each of these virus particles is in the midst of creating thousands of copies of itself.
This huge population of virus particles, making mostly mistaken copies of themselves, is bound by the laws of statistics to come up with some random mistakes that actually work better than their parent virus particles.
This has now happened at least three times.
Once in the UK by September 2020, once in South Africa by December 2020, and once in Brazil by January 2021. These three variants of COVID are each some combination of more infectious and less susceptible to antibodies/vaccines than the original China variant discovered in December 2019, and they've each gone global thanks to continued air travel.
You could call the UK variant COVID-20a, the South African variant COVID-20b, and the Brazilian variant COVID-21a.
-----
Scientists are working to figure out how much more infectious and how less susceptible to antibodies/vaccines these new COVID variants might be.
In general, they seem to be 50% more infectious, and 50% less susceptible to antibodies/vaccines. But we do not know precisely yet.
We know that some people who have already been infected with COVID-19 have been reinfected with one of these three variants.
We know that the vaccines we've already approved are less effective against some of these variants.
As a result, the vaccine manufacturers are already working to update their vaccines to match these variants.
-----
Meanwhile, a quintillion COVID particles are busily making thousands of copies of themselves at this moment, and most of these copies will be mutations. Most of these mutations will not work. Some of them will work just the same as their parent, but with a different "color" coat. Occasionally, one of them will work better than their parent, and a new variant will have emerged. Maybe the next new variant will appear in the US, maybe in India, maybe in Sweden, maybe in Mexico. Who knows, the process is entirely random. But there's no reason to think we're done with COVID mutations after three new global variants have emerged in a matter of months.
This is why COVID is not going away anytime soon. This is why even if you've had COVID before, or even if you've been vaccinated, you may get COVID again. This is why we're probably going to need annual booster shots for COVID like we do for influenza. This is why I wonder whether we'll ever go back to the old normal, or whether we'll just get used to some average number of daily deaths from COVID, like we're used to an average of 100 daily deaths from influenza in the US.
The chances are you'll get COVID someday, or you'll get COVID again someday. So what will our new normal look like? And for how long will you remain in Quarantine?