Herd immunity is in the news these days, and, no, it has nothing to do with Devin Nunes. (Because cow. And cows come in herds. And Devin Nunes (R-CA) keeps suing a talking cow on Twitter. Because Congress doesn't have more pressing problems at the moment. Just a little joke to help soften the pain of watching the Republic die. But I digress.)
The idea is straightforward. To halt an epidemic, you don't need everyone immune, just enough people to break the chain of transmission. COVID isn't immortal. Think of infection as starting a clock. The virus has a finite window of opportunity to infect another host before its current host becomes inhospitable, either because the host's immune system has come on-line or the host has died. If it doesn't jump to a new host by the time the clock runs out, it goes down with the ship.
It's like The Hidden, except without Ferraris and strippers.
Now for the bad news.
The bad news is herd immunity often requires immunity rates above 90%. We've achieved that for some diseases -- it's why smallpox, polio, and rinderpest are no longer the menace they once were. But that was back when Americans listened to reason. Herd immunity requires vaccination, and vaccination requires compliance.
You and yours may join the herd, but your idiot coworker or your idiot in-law refuses because [ random poptart ] or [ random sportsballer ] or Wink Martindale decides today they're an infectious disease expert who sez you don't have to do your part because reasons. So we're really fighting two diseases: the COVID and the stupid. And as the saying goes, none of us is as stupid as all of us.
The question becomes: What degree of noncompliance can we tolerate and still achieve herd immunity? For an answer, we turn to Javascript.
The squares are your Sims or your Kerbals or your Oids, whatever, going about their daily routine from home to work to grocery store, etc. Reds are infected, greens are susceptible, and blacks are immune. Set the population density and herd immunity fraction using the sliders. Infected eventually become immune, adding to the baseline immunity.
A simulation ends when there are no more infected or no more susceptible. A win is if the run ends with susceptibles remaining in the population. They have been protected by herd immunity. A lose is if the run ends with no susceptibles left. Your herd immunity was insufficient. Tut mir leid.
You should discover that the higher the baseline immunity the more reliably you'll achieve a good outcome. Therein lies the rub.
The best case immunity scenario is a COVID-19 vaccine. That goal is challenging but attainable. Viruses are complicated but they aren't sorcery. COVID isn't voodoo. It's not caused by curses or black magic. It isn't divine punishment for allowing women to wear trousers or electing Donald Trump.
Unfortunately, there is still much unknown about COVID-19 and any unknown makes vaccine development take longer. Currently, the end is not in sight. This is fueling calls from the Right to simply let COVID run its course. Herd immunity is for closers. Sure, we'll get our hair mussed a little, but there's like 50,000 deaths from the ordinary flu every year. What makes 150,000 COVID deaths special?
The answer is 150,000 COVID deaths in a few months. Do we not teach "calendar" in school anymore?
So to you tough guys on Facebook or AM radio advocating the Lord of the Flies solution, I'll only say this: You go first.
Yeah. That's what I thought.
In the meantime, we work with humbler tools. Social distancing and masks. These are not immunity, but they reduce the force of infection, which has a synergistic effect. In the sim, this is equivalent to reducing the population density. The unifying theme is "reduced opportunity for transmission."
Alas, that theme is undermined when a Republican governor declares mask mandates to be illegal (not making this up), or when a Republican sheriff declares mask wearing to be illegal (ibid), or when a Republican shouty interrupts a townhall to declare social distancing is the work of Satan (ibid).
We want to do what infectious disease experts recommend, but the lady wearing a QAnon shirt and a halo of dead squirrels deserves to be heard. No, she doesn't. Starting now, that sentence can end at the word "but." If you want this to end, it's time for the crazies to be pushed aside. Corralled. Put to pasture.
Trying to reason with them is a moo point.
The idea is straightforward. To halt an epidemic, you don't need everyone immune, just enough people to break the chain of transmission. COVID isn't immortal. Think of infection as starting a clock. The virus has a finite window of opportunity to infect another host before its current host becomes inhospitable, either because the host's immune system has come on-line or the host has died. If it doesn't jump to a new host by the time the clock runs out, it goes down with the ship.
It's like The Hidden, except without Ferraris and strippers.
Now for the bad news.
The bad news is herd immunity often requires immunity rates above 90%. We've achieved that for some diseases -- it's why smallpox, polio, and rinderpest are no longer the menace they once were. But that was back when Americans listened to reason. Herd immunity requires vaccination, and vaccination requires compliance.
You and yours may join the herd, but your idiot coworker or your idiot in-law refuses because [ random poptart ] or [ random sportsballer ] or Wink Martindale decides today they're an infectious disease expert who sez you don't have to do your part because reasons. So we're really fighting two diseases: the COVID and the stupid. And as the saying goes, none of us is as stupid as all of us.
The question becomes: What degree of noncompliance can we tolerate and still achieve herd immunity? For an answer, we turn to Javascript.
susceptible (g) / infected (r) / immune (k)
(0%) --- immunity --- (100%)
(sparse) --- population --- (dense)
---
(0%) --- immunity --- (100%)
(sparse) --- population --- (dense)
The squares are your Sims or your Kerbals or your Oids, whatever, going about their daily routine from home to work to grocery store, etc. Reds are infected, greens are susceptible, and blacks are immune. Set the population density and herd immunity fraction using the sliders. Infected eventually become immune, adding to the baseline immunity.
A simulation ends when there are no more infected or no more susceptible. A win is if the run ends with susceptibles remaining in the population. They have been protected by herd immunity. A lose is if the run ends with no susceptibles left. Your herd immunity was insufficient. Tut mir leid.
You should discover that the higher the baseline immunity the more reliably you'll achieve a good outcome. Therein lies the rub.
The best case immunity scenario is a COVID-19 vaccine. That goal is challenging but attainable. Viruses are complicated but they aren't sorcery. COVID isn't voodoo. It's not caused by curses or black magic. It isn't divine punishment for allowing women to wear trousers or electing Donald Trump.
Unfortunately, there is still much unknown about COVID-19 and any unknown makes vaccine development take longer. Currently, the end is not in sight. This is fueling calls from the Right to simply let COVID run its course. Herd immunity is for closers. Sure, we'll get our hair mussed a little, but there's like 50,000 deaths from the ordinary flu every year. What makes 150,000 COVID deaths special?
The answer is 150,000 COVID deaths in a few months. Do we not teach "calendar" in school anymore?
So to you tough guys on Facebook or AM radio advocating the Lord of the Flies solution, I'll only say this: You go first.
Yeah. That's what I thought.
In the meantime, we work with humbler tools. Social distancing and masks. These are not immunity, but they reduce the force of infection, which has a synergistic effect. In the sim, this is equivalent to reducing the population density. The unifying theme is "reduced opportunity for transmission."
Alas, that theme is undermined when a Republican governor declares mask mandates to be illegal (not making this up), or when a Republican sheriff declares mask wearing to be illegal (ibid), or when a Republican shouty interrupts a townhall to declare social distancing is the work of Satan (ibid).
We want to do what infectious disease experts recommend, but the lady wearing a QAnon shirt and a halo of dead squirrels deserves to be heard. No, she doesn't. Starting now, that sentence can end at the word "but." If you want this to end, it's time for the crazies to be pushed aside. Corralled. Put to pasture.
Trying to reason with them is a moo point.
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