Coronavirus

# What's the Herd Immunity Threshold for the COVID-19 Coronavirus?

## Estimates range from 70 to 10 percent.

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"About 30 percent of people in Stockholm have reached a level of immunity," Sweden's ambassador to the U.S. told NPR on April 26. "We could reach herd immunity [to the coronavirus] in the capital as early as next month."

The comment turns out to have been a bit hasty: The report on the city's infection rate that the ambassador seems to have been referencing had already been withdrawn without explanation four days earlier. But the larger issue of herd immunity remains important.

Herd immunity is the resistance to the spread of a contagious disease that results if a sufficiently high proportion of a population is immune to the illness. Some people are still susceptible, but they are surrounded by immune indviduals, who serve as a barrier preventing the microbes from reaching them. You can achieve this through either mass infection or mass vaccination.

Until there is an effective COVID-19 vaccine, the only way to achieve herd immunity would be to allow the microbe to infect enough people to form that barrier protecting the susceptible. The breadth of the barrier required to achieve herd immunity depends in large part on just how contagious a specific disease is. For example: In a susceptible, unvaccinated population, each measles carrier will infect an estimated 12 to 18 other people. In the nomenclature of epidemiology, the basic reproduction number or R0 ("R naught") of measles is 12 to 18.

The classical formula for calculating a herd immunity threshold is 1—1/R0. With measles, that means 1—1/18, or a threshold of 94 percent. In general, the higher the R0, the higher the threshold required for achieving herd immunity. Other important factors in calculating herd immunity thresholds include the number of social interactions and their durations, innate differences in individual immune responses, and divergent exposures to the infectious microbe.

While there is still some debate about this, the R0 of the COVID-19 coronavirus without interventions is generally estimated to be between 2.2 and 2.7. If the R0 is below 1, that means the outbreak is abating as fewer and fewer people are infected; if it remains above 1, the epidemic is ongoing. The goal of social distancing practices is to stem the epidemic by driving the R0 of the coronavirus below 1.

Of course, achieving herd immunity would also eventually result in an R0 that falls below 1 and a declining number of infections.

Most the evidence so far suggests that people who recover from a COVID-19 coronavirus infection do, at least for a time, develop immunity to the microbe. If that's true, what is the disease-induced herd immunity threshold for the COVID-19 coronavirus? Various epidemiologists offer different answers, depending upon their estimates for the disease's R0 and other variables, but most have converged on a threshold at around 60 to 70 percent.

More recently, some researchers have suggested that this threshold may be too high. In a new preprint, three mathematicians from Sweden and the United Kingdom, using an R0 of 2.5, calculate a reduction in the herd immunity threshold from 60 percent to 43 percent by incorporating some assumptions with respect to populations' social activity levels and age structures.

A couple of new reports speculatively lower the possible herd immunity threshold for the coronavirus to just 10 to 20 percent of the population. This conjecture depends chiefly on assumptions about just how susceptible and connected members of the herd are. In their preprint, a team of European epidemiologists led by the Liverpool School of Tropical Medicine mathematical bioscientist Gabriela Gomes explains how this might work.

If highly susceptible herd members become infected and thus immune first, the preprint says, their subsequent interactions with the still-uninfected will not result in additional cases. Basically, the virus stymies itself by disproportionately removing those most useful to it from contributing to its future transmission. In addition, if herd members are very loosely connected and interact with one another rarely, the virus will have a much harder time jumping to its next victims. Sustained social distancing aimed at flattening the curve of coronavirus infections and cases mimics this effect.

Adopting insights from the Gomes article, the British statistician Nic Lewis suggests that Stockholm County in Sweden may indeed have already achieved herd immunity. But if formerly standoffish herd members start frequently hanging out together in, say, bars, restaurants, theaters and baseball games, the percent of the population needed to achieve herd immunity will of course rise.

There are no solid estimates for the percentage of the U.S. population that has already been infected by the coronavirus, but Youyang Gu and his team at COVID19-Projections estimate that right now the number is between 2.2 to 4.7 percent. That would mean that somewhere between 7.3 and 15.5 million Americans have been infected. A similar result emerges from a very rough calculation that multiplies the number of confirmed cases at 1.4 million by a 10-fold factor of undiagnosed cases and infections. (The 10-fold factor is derived from data recently reported by Indiana University researchers.)

The upshot: The U.S. as a whole is not yet close to achieving even the speculatively low estimate of the herd immunity threshold.

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1. So now we have a new number to play with, calculated from the other know to be unreliable numbers.
Wonderful.
You want herd immunity, repeal all the fascist bullshit and let mother nature sort it all out for us.

1. Mother Nature can sort it all out. But Mother Nature only has one tool to do the sorting with: Death and Disease.

Which is why we’re trying to flatten the curve and ease the rate of infections, to keep the death toll down. But you don’t give a shit about that. It’s okay to you if someone else dies.

This is not an either/or situation. Just because the government went to far with the lockdowns does NOT mean it’s okay to be attending raves and licking doorknobs. Wear your fucking mask.

1. Otherwise known as Evolution. BOOOOO this evolution bullshit right Brandy?

You really are an idiot.

1. Evolution is great, until you’re the one on the chopping block.

1. Again. I’m sorry that your parents told you you would live forever. Life sucks. People die some younger than others. Some not. Bit that’s life. Go yell at your parents for not explaining this to you.

2.8 million americans die every year. And yet it took 80k mostly elderly deaths to realize you’re not immortal.

Just a tragedy on your part.

1. We “flattened the curve” and I’ ve clear road for miles, what in the fuck is the holdup? Oh. you don’t want to miss the opporutnity to bash Trump. I forgot, if ever there’s a chance to trip Trump, you don’t want to let it pass by!

Why didn’t you say for in the first place? If you did that, I wouldn’t have need to read your comment and process your bullshit. When you start your car and take off, you’ve assumed the risk of being a NHSB fatality.

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2. We “flattened the curve” and I’ ve clear road for miles, what in the fuck is the holdup? Oh. you don’t want to miss the opporutnity to bash Trump. I forgot, if ever there’s a chance to trip Trump, you don’t want to let it pass by!

Why didn’t you say for in the first place? If you did that, I wouldn’t have need to read your comment and process your bullshit. When you start your car and take off, you’ve assumed the risk of being a NHSB fatality.

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2. We “flattened the curve” and I’ ve clear road for miles, what in the fuck is the holdup? Oh. you don’t want to miss the opporutnity to bash Trump. I forgot, if ever there’s a chance to trip Trump, you don’t want to let it pass by!

Why didn’t you say for in the first place? If you did that, I wouldn’t have need to read your comment and process your bullshit.

3. “Otherwise known as Evolution. BOOOOO this evolution bullshit right Brandy?”

Apparently science is only important if it supports Brandybuck’s preconceived conclusions.

1. Much like the ‘climate science’ that inevitably demands centralized economies.

Kill yourself, bitch

1. I have it on very good authority that *masks don’t work*

1. The CDC said they don’t initially, which was enough to convince me to wear one. When the government tells you not to buy something while they hoard it themselves, it’s a decent indicator that the government thinks it’s a good thing to have.

2. Masks work if you have the disease. It absolutely helps keep people from spreading it. I will laugh every time one of the maskless dumbasses in walmart get tossed into jail for not doing the obvious. I think before the end of the year is up we’ll be seeing that.

1. Uhmm. You are missing a whole lot of steps there fool.

2. Masks work if you have the disease.

If you’re wearing a cloth or OTC mask and you have it if you breathe air shoots out around it–as anyone with glasses can attest.

If you cough, or sneeze, or shout–anything that gives a big exhalation, the mask sieves the larger droplets, retaining most and letting an ultrafine mist of exhalate through.

This strips away the moisture that causes C19 to fall quickly and allows it to aerosolize–which, while not an ideal environment for it, allows two things.

Further travel in the air before it’s dead/drops, and a higher survival rate for those virions that CAN make it to a new host, helping to evolve an aerosol version.

1. Actual studies show this? Or is this your brilliant theory.

2. Source?

Regardless, masks reduce viral load exposure – which is the only explanation for the extended period of time before symptoms appear, and of course, the front line medical workers dying.

So, if a sick person has on a mask, you’re right, viral particulate will expel through the sides and everywhere else around the edge. But now it is dispersed into countless little particles that may linger in the air. The longer you stay in that enclosed area, the more you will suck in. It takes an above zero (research says at least 20, to as many as hundreds of particles) to become infected.

Wearing a mask – any mask – has been shown to reduce viral load by 55% or more depending on the mask and the user.

So if both parties wear masks, you’ve essentially reduced your exposure to insignificant amounts. If they sneeze or cough – get out of the area. And since just talking may even spread it, do us all a favor and stfu.

3. I remember, back in the late ’80s, some people said: “Latex rubber condoms have natural pores large enough for HIV particles to pass through” — which was true in itself.

But then the same people said: “Therefore, condoms aren’t really useful at preventing the transmission of HIV” — and these people were wrong and scientifically ignorant to say that.

3. Which is why we’re trying to flatten the curve and ease the rate of infections, to keep the death toll down.

Ease the rate of infection to keep hospitals from being overrun, not to prevent people from being infected at all.

The steep curve/flat curve graph that has been floating around the last couple months is not “we would have had 60% of the people infected, but we flattened the curve and now only 20% will ever get it”

That graph means 60% of the people will get this no matter what is done, so the only deaths you can really prevent are the ones caused by lack of available care.

As we are in most places underutilizing healthcare resources, they’ve gone too far and will in all probability, because people aren’t being allowed to get out and get it during the season when its likely to be least virulent, create the very thing they keep warning about….a worse wave come winter.

1. Sorry, accidental flag. Fat fingers.

2. Yep. The shift in the stated purpose of the “social distancing” is one of the more disturbing things here. We are well past the possibility of containment. The only thing now is to try to mitigate problems with the healthcare system and learn to live with it. Hopefully without convincing people that wearing masks everywhere is a normal thing to do if you don’t have something wrong with you.

4. “Flattening the curve” does NOT change the area under it! That means, the SAME number of people will become infected under a flat curve as under a steep one — just over a longer period of time.

The only gain in flattening is the possible one of avoiding overloading hospital facilities, and that is only if your area is governed by a buffoon like Cuomo who closed hospitals and got rid of PPE and ventilators.

5. Let’s try one more time. FLATTENING THE CURVE DOES NOT CHANGE THE TOTAL NUMBER OF DEATHS from the disease. “Flattening the curve” prevents hospitals from getting overwhelmed – which we once thought might be a threat but subsequent data have shown was never a significant risk.

The lockdowns will not stop the spread of this disease. They can’t. They can only slow the spread. Slowing the spread might be useful – but only if there is a mechanism that actually changes the disease outcomes. In this case, there aren’t. The same percentage are eventually going to get sick and the same percentage are eventually going to die. All you’re doing is spreading those factors out over time.

6. It was never going to reduce the death toll. Back in march, Fauci was sanguine about this. It was about not overwhelming hospitals, not reducing covid-19’s death toll. Bar a vaccine (unlikely and far off), nothing will stop Covid-19 from achieving enough infections to reach herd immunity in the long term. Those flattened curves have the same area under them as the non-flattened curves, they just spread that area out.

7. “Which is why we’re trying to flatten the curve and ease the rate of infections, to keep the death toll down. ”

No. We tried to flatten the curve for other reasons entirely.

In our population there exists a subset of people for whom infection by COVID is a death sentence. I’ll call them Group A. Once exposed, there is no amount of medical assistance that is going to save them (e.g., 80% of people who get put on ventilators and in ICU care for this still die). Short of magically knowing who those people are and placing them in sterile bubbles for the rest of their lives, there is likely nothing that we can do to prevent their deaths.

There exists another subset of people for whom infection with COVID is going to cause severe illness, but with the miracles of modern medicine, ICU care and ventilators, they can eventually recover. Call this Group B.

There are other groups: those for whom COVID infection results in virtually no detectable symptoms (may be upward of 50% of infections) [Group E]; those for whom COVID infection causes mild flu-like symptoms that they recover from without medical intervention (may be upward of 40% of infections) [Group D]; those for whom COVID infection results in severe illness, perhaps requiring hospitalization but not extraordinary care (no ICU, no ventilators) [Group C]. Let’s ignore these, because except for the small last group, they resolve on their own.

Because we really cannot separate Group A from Group B until after extraordinary care fails to save them (must have been Group A) or they recover (must have been Group B), we tried to slow down the rate of infection so that we did not overwhelm the hospitals all at once with all the Group A and B people at the same time. Because if we ran out of ventilators, the next person that needed one might be from Group B and might die as a result of not having the ventilator.

In other words, “flattening the curve” was, by definition, trying NOT to save every life–we know those in Group A are dead anyway–but to hopefully ensure there were enough resources available to save as many Group B people as possible. Maybe a little bit of trying to keep from flooding the hospitals with Group C folks, again to save the Group B people by not overwhelming resources.

Sadly, the folks in Group A will die from COVID sooner or later, because the virus is in the wild and half-assed lockdowns that let people go the the grocery store, Wal-Mart, and Home Depot will not protect the people in Group A. The virus is in the wild and those folks in Group A will eventually be exposed and they will die from it. Period. The only way we reduce the size of Group A is when they die from something else before they are exposed to COVID.

1. Well stated. People need some fucking perspective on this. It’s not a roll of the dice. We know who is likely to be severely affected by this.

8. You are confused about “flatten the curve”
The area under a curve is the same whether it is flattened or not.
The same number of people are going to get sick, and the same number will die, whether you quarantine or not.
The only difference is the hospitals are not overwhelmed by all the cases occurring at the same time.
So that the heart attacks and appendicitis cases don’t die in the parking lot due to all the beds being filled by corona patients.

9. Flattening the curve was to give the hospitals time to prepare. None of them are overloaded now. Flatten the curve too far out and we’re back to cold and flu season with much lower immunity than we would have otherwise. It will backfire.

10. You obviously do not know what flattening the curve means. It has never been about keeping the death toll down. That’s a little sleight of hand the media and politicians have played on us. Flattening the curve means to take the cases of a given infection and delay some of them until a later date, so that the hospitals have enough capacity to attend to anyone who needs additional care. The total area under the curve (representing the number of people who get sick) is unchanged, but the shape of it is flatter.

The only part of the US that needed that was New York City, and only for a short time. The rest of the US had, and has, excess capacity in the hospitals, so no curve flattening was needed.

The vast majority of people are not seriously affected when infected with corona. Those people can take the hit and provide the herd immunity that will prevent the vulnerable from having to take a hit that is more likely to kill them. Hiding everyone forever won’t protect them… anything we do to slow the rate of infection is just preventing herd immunity and keeping the pandemic active for a longer time, which makes sure that the vulnerable remain in the line of fire.

Sweden is well on its way to having the lower-end estimate of percentage of the population with the antibodies that will confer herd immunity, which is the only thing that can protect that small minority of the population that is at risk of death from corona. We in the US have tried the turtle approach, and as a result, we’re still far from having the one thing that can protect the vulnerable.

11. Mother nature also has the human immune system to work with. It’s pretty good.

12. Flattening the curve only prevents the deaths that might have happened due to lack of care from health care infrastructure being overwhelmed. Since even NYC has insisted continually that their hospitals aren’t being overwhelmed, it would seem that there’s no additional measure that could have been taken that might have significantly reduced the current number of deaths (and unless the hospitals get overwhelmed at some point, whatever the final total comes out to would have required an entirely different strategy to possible reduce). Combine that with the estimates that face-covering/social distancing alone would reduce the spread by as much as 80% and the reports that 2/3 of the known “new infections” over the last month in NYC were people who had been following the “self-quarantine” rules and there is at least a case for considering the possibility that the “lockdown” protocols aren’t really necessary and may not actually be particularly helpful. At this point, the pols who have pushed them so hard might even be simply afraid of losing some face if they’re forced to admit that it’d possibly be safe to let people out again; in CA, Gov Newsom has been laying the groundwork for weeks to blame any uptick in cases when the lockdowns are relieved (something which many experts have predicted will happen whenever that happens unless it’s after mass vaccinations) on the idea that the relief was done “too soon”, and in L.A. the county health commissioner has made reference to 500 new cases of the previous week (in a county with 10 million people where many individual ERs typically handle 200+ patients daily) as being severe enough to warrant slowing the relief timeline despite the fact that some hospitals in the area have been talking about possibly having to furlough staff due to lack of patients, and the USN hospital ship left the harbor after treating 77 total patients over 6 weeks (and being hit with a Covid outbreak among their crew). When the hospitals start talking about layoffs, it’s probably safe to say they’re not close to being overwhelmed.

2. How is herd immunity going in Sweden? 90% higher death rate than neighboring countries and the curve just has not flattened at all.
Norway is down to 23 new cases a day from a high of 425; Finland is down to an average of 40 the last week; active cases in Sweden have soared from 9000 to 20,000 in the last month, and deaths have risen from 900 to over 4000 in the last month. Have they achieved herd immunity: not by the evidence.

1. I just looked at the trend for Sweden. New cases have been dropping and are now hovering around 59 cases per million per day which is not bad.

New York City, similar in population is around 88.

2. Citation, please. The statistics you cite are contradicted by the trend data available from worldometers.

And as a side note, absolute numbers are meaningless as measures of disease progression. You need to show your conclusions as per-capita numbers for any reasonable comparisons to be valid.

1. Yes, more testing means higher numbers. Confirmed cases is a meaningless number without context.

3. Who gives a shit if deaths have risen in a month. Every month on record deaths have risen numbnuts.

How the fuck do you think they’re going to achieve their goal of herd immunity? And guess what? 1500 of those 3600 deaths were 80-90 age group. So it’s not like anyone has really died – those old af health care hoarders were going to die from the next cold shower they got into anyways.

1. Yeah, deaths are not going to go down. The rate of deaths has been going down steadily for some time now.

4. yeah, part of acquiring herd immunity is people catching the virus. Neighboring countries have fewer cases now but will be more exposed to round 2 in the fall and winter cold and flu season.

5. Whether or not Sweden has achieved herd immunity, they’re unquestionably closer to doing so than Finland.

As others have pointed out here, “flattening the curve” is about postponing cases, not about preventing them altogether. The fact that some places that have taken more aggressive measures toward flattening have fewer cases so far (although many other countries that have done more to achieve “flattening” aren’t doing nearly as well as Sweden so far) is a fact that’s both predictable and not really indicative of the “big picture” result of how various counties will have ultimately fared when they do achieve herd immunity either through vaccination (if possible) or through sufficient levels of exposure/infection (which will eventually happen everywhere unless mass vaccination becomes possible).

However herd immunity is reached, there’s likely nothing else that’ll significantly inhibit the spread of the virus over an extended timeline. Until that point is reached in any given country, the number of cases/deaths there should be considered to be an “interim” number, and there’s no possible way to know if any number of infections are actually being prevented rather than merely being postponed. As long as local medical infrastructure isn’t overwhelmed, there’s little reason to believe that any meaningful number of deaths could have really been prevented (although some could maybe have been delayed).

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4. Nations and states are quietly easing out of lockdown because the choice is clear..ease out or die. They won’t say that lockdown was a mistake. Who would benefit from an admission like that?

1. No one will. It makes me want to puke. This is the biggest scandal and failure of government of my lifetime. Will people ever learn the right lessons from it?

2. 94%. Not 0.94%.

1. B: Been trying to say thank you for catching the typo, but some website changes have prevented me from logging into the comment section until now. It’s fixed. Enjoy your weekend.

3. Estimates range from 70 to 10 percent.

In other words, we don’t fucking know, so your wild-ass guess is as good as mine.

1. In other words, we don’t fucking know, so your wild-ass guess is as good as mine.

I mean, Neil Ferguson said between 50 and 500,000 people would die from mad cow disease (or whatever, I am not going to google the specifics on his well known BS), and we were supposed to believe his predictions at face value… A range of 10-70% seems as precise as we need these days.

4. I’m already seen posts from “herd immunity deniers”. People who claim it’s a conspiracy, that no such thing exists. My guess is that these people are either Anti-Vaxxers (for whom the concept of herd immunity imposes some social obligations to get vaccinated), or Contrarians (those people who instinctively believe the opposite of everyone else, unless everyone else happens to also be a Contrarian).

1. Difficulty… you can’t post a citation of someone denying herd immunity. But go for it. Everything else you say is bullshit.

2. Without addressing whether anyone should or shouldn’t get vaccinated one way or the other:

So, absent a vaccine, what’s the effective difference between herd immunity and everybody contracting the disease? Show your work.

Furthermore, in order to *achieve* *herd* immunity, the *herd* must act in relative unison (developing a vaccine, distributing a vaccine, testing immunity, maintaining immunity, etc.), conspiracy is required.

Despite your #IFLSMore elitist bullshit, half the problem or more has nothing to do with science. FFS, we went over this bullshit in January when you fucktards said “everybody will have to self-quarantine” and meant “we’re going to lock everyone inside and trash the economy, by law.”

1. Vaccines increase herd immunity. I mean, duh. But without a vaccine you get the herd immunity by a lot of people getting sick and dying. Vaccines prevent that. Two ways to achieve herd immunity, and vaccines are by far the safest way.

Herd immunity is NOT about acting in unison. It’s merely about a certain percentage of the population having resistance. The reason we have herd immunity to Rubella is because most people have been vaccinated against the Rubella. In places where the vaccination rate has dropped due to antivaxxers you start to see cases of Rubella crop up.

“Immunity” is not the best word. It’s really resistance. Vaccination is not immunity, it’s resistance. But resistance still slows the spread of a disease through a population.

I am NOT against ending the lockdowns. Hell, the fastest way we can build up a herd immunity is for people to be interacting with each other. Hopefully we can do that in a safe and controlled way, rather than everyone heading to the crowdest bar to spend their latest Trump Check.

1. Wow
What a cowardly little bitch you are

1. We “flattened the curve” and I’ ve clear road for miles, what in the fuck is the holdup? Oh. you don’t want to miss the opporutnity to bash Trump. I forgot, if ever there’s a chance to trip Trump, you don’t want to let it pass by!

Why didn’t you say for in the first place? If you did that, I wouldn’t have need to read your comment and process your bullshit. When you start your car and take off, you’ve assumed the risk of being a NHSB fatality.

2. Vaccines increase herd immunity. I mean, duh. But without a vaccine you get the herd immunity by a lot of people getting sick and dying. Vaccines prevent that. Two ways to achieve herd immunity, and vaccines are by far the safest way.

OK, so if I ask a question that’s immaterial and no one asked, do I get the answer to the question that I actually did ask?

For somebody who’s so hard on anti-Vaxx idiots, you sure are regurgitating factoids mindlessly like an NPC.

Now, without a vaccine, what’s the difference between herd immunity and everybody who can contract the disease contracting it?

Maybe I should put it another way: Isn’t the only way any herd *fails* to achieve herd immunity is by getting annihilated?

And, more broadly: Assuming we can’t annihilate a herd of humans to prove our assumptions correct/incorrect, aren’t we fundamentally talking about an untestable hypothesis?

1. I have been generally correct about COVID-19. I am changing my position and answering a question about herd immunity here. We won’t achieve herd immunity (meaning an absence of the virus in the population). COVID-19 will find a place on the spectrum of endemic to seasonal viruses that we live with. Treatments will improve marginally. Healthy people don’t die from COVID-19.

3. A lot of people getting infected not sick. At least 50% of infected are asymptomatic.
A lot of people dieing? Depends on how you calculate a lot of people. Do we calculate based on percentage infected. Then a lot is debatable.
Also, a question Bailey didn’t ask is how many people are actually susceptible hosts. There is a percentage that their immune system eliminates the infection before it can successfully infect them. We know this plays a role in any outbreak. Those exposed and do not develop illness are not all asymptomatic carriers. Some never become infected because their immune system destroys the pathogen before it has a chance to infect the host. This can be because the illness is similar to another pathogen that the host was already exposed to (cross immunity) or because of a genetic mutation that makes their immune system better at identifying and combating incursions. There is evidence that a mutation in some Europeans made them naturally immune to plague. This was more likely to have been passed down to future generations. Thus, subsequent outbreaks of plague over the next couple of centuries were less severe. Each time a new outbreak occurred though, it weeded out those who were susceptible. This is hypothesized as to be why there hasn’t been a serious outbreak of plague since the 17th century. It is also theorized that this mutation has made Europeans more resistant to outbreaks, especially bacterial.
The question no one seems to have addressed is how large is the actual population of potential susceptible hosts? Yes, it is a novel virus (but one similar to a number of viruses that already exist and are pathogenic to humans). Almost all of the projections, even in this story, seem to assume that the population of susceptible approaches 100%. Debated about R0 are strictly about how transmittable it is, not how likely once it is transmittable that the virus will actually reach a point that is defined as infected. By infected I mean is capable of invading a cell and reproducing. Asymptomatic are infected. Naturally immune will not be infected. Their innate immunity gives them protection.
There is also another group, those who receive a low viral load, not enough to he fully infected but have been exposed. This group will develop some acquired immunity, making it less likely they can become infected later. This is how vaccines work.
For us to understand how large the herd immunity needs to be we have to understand how many develop acquired immunity via low subpathogenic exposure, asymptomatic illness, symptomatic illness and those whose innate immunity already protects them.

1. Naturally immune and subpathogenic immune sound similar, but the mechanism is different. In anyone who isn’t immunocompromised, your innate immunity recognizes and begins attempting to eradicate foreign bodies. Infections occur if the pathogen survives this initial response and begin reproducing. In those with natural immunity the initial exposure to the pathogen is less relevant, because short of a massive direct infection their immune system is capable of stopping the pathogen from reproducing. In those who receive subpathogenic doses, the number of pathogens that they’ve been exposed to is small enough that they can effectively destroy the pathogen before it can reproduce. It is far more dose dependant then natural immunity.
Both groups however are not totally immune, because a large enough exposure can overwhelm just about any immune system, or they may become immunocompromised for other reasons (stress, poor diet/nutritional deficiencies, co-morbidities and infections etc).

1. Anybody who knows even a little bit of virology has heard the stories and understands the concepts about milk maids being immune to smallpox and typhoid Mary.

1. Cross immunity.

1. Cowpox until 2016 was the only approved smallpox vaccine in the US and was what Jenner first used to combat smallpox.

1. Actually, we don’t know when, due to some sloppiness in the maintenance of virus stocks, another strain that includes genes from smallpox inadvertently replaced the vaccinia vaccine line! No apparent harm, though.

1. Add in those who survived smallpox before the vaccine had some genetic advantage in their immune system that they passed on, and the poorly (as of yet) role of epigenetics…

2. Milk maids, sure. Typhoid Mary however, simply tolerated what doctors at the time described as a ‘massive infection’ (albeit bacterial) for decades while others around her succumbed to the disease in months or even weeks.

2. But more important to the current discussion than cross-immunity (which is a type of less-specific specific immunity) are nonspecific (innate) immunity and consideration of things like dose and route of infection.

Before the use of vaccinia (cowpox) came into wide practice, immunization with actual smallpox was practiced. Why did it work? We don’t know exactly. There may have been some degree of attenuation in the inoculum used, but we do know there were sometimes deaths or debility from it, yet experience showed it was safe enough to be worthwhile. It’s likely that the route of infection was important — infecting the recipient by a means that slowed the spread of the virus into its usual host tissues in the body while allowing time for specific immunity to develop.

This is also why paralytic polio was not an epidemic disease until or close to the 20th Century. People were exposed early in life to this widespread virus that usually only colonized the GI tract. It was only when sanitation improved, eliminating dysentery, cholera, and to some extent hepatitis A, that exposure to the polio virus was deferred and left populations subject to epidemics that included many paralytic cases.

1. The first small pox vaccinations did use a dangerous method of sub dose exposure but Jenner’s vaccine used cowpox, which wasn’t pathogenic to humans but provided some cross immunity to small pox.

2. Another example is allergies. Allergic reactions are the result of immune and subsequent inflammatory response to an allergen. Most people don’t have allergic responses because their immune response doesn’t trigger an inflammatory response. In those with allergies, there is a subsequent, noticable inflammatory response.
There is three ways to treat allergies. Most people can get by with just taking meds that inhibit inflammation. The second way is to avoid the allergen all together. The third way is to give small doses of the allergen to modify the immunite response and thus hopefully inhibit a dangerous inflammatory event.

1. The first small pox vaccinations did use a dangerous method of sub dose exposure but Jenner’s vaccine used cowpox, which wasn’t pathogenic to humans but provided some cross immunity to small pox.

2. yeah, ideally you get the younger and healthier people exposed by, for instance, going to work, eating at restaurants and hanging out at bars. Then when Round 2 hits in the next cold and flu season, it spreads far slower and the elderly and sick are less at risk.
Only a total moron like Gavin Newsom would keep healthy people at home in the summer.

4. you get the herd immunity by a lot of people getting sick and dying.

Herd immunity has nothing to do with dying. You could have 100% dead or 0% dead, it makes no difference. Your lumping that in shows your ignorance and bias and fear.

5. I noticed you skipped over my request for a single citation.

6. By the way…

“herd immunity by a lot of people getting sick and dying.”

Dumbest shit since the last time JFree chimed in.

You dont have to die to get partial immunity.. like the majority of covid1984 patients that were asymptomatic.

7. To some extent, it is about concerted action, at least at the margins. That’s how we dealt with childhood diseases before there were vaccines for them: by deliberately getting our children together when one of them had the measles or whatever. It was recognized that it was safer to get even the unattenuated virus during childhood than later in life, and it was more or less assumed that as long as it was fairly prevalent, you weren’t going to duck it your whole life, so why not get it at the most convenient time?

1. What utter horseshit. My dad was a kid during the polio and pre-vaccine years. He remembers town facilities (like pool, school, etc) shutting down at times – multiple times per year – for schools they were far more common than weather closures – and being told ‘It’s because someone has the measles/etc’. And he lived in a small county seat type town.

The two biggest causes (by far – there really is no third place) for the increases in life expectancy in the 20th century are antibiotics and childhood vaccines. That means kids died then and odd thing is parents back then didn’t just say ‘Well we all gotta die sometime so why not at a convenient time’

8. Oh get a grip. Without a vaccine you get the herd immunity by a lot of people getting sick and recovering and some people not recovering. Most of the people who have died were already in nursing homes because they were already dying! And the dirty little secret is that a very large percentage of those were dementia patients who no longer had any meaningful connections with friends or family. No one is allowed to say that, but it’s true. I’ve worked in those nursing homes, and I promise you, and tragically large percentage of patients have been parked and forgotten by families who never give them a thought anymore.

1. Research backs this up. When I was a nurse I remember a lecture I attended where the presenter stated that if family visits nursing home residents during 12 times a year their first year, that the second year on average it will only be 6 times, then 3 and so on. We, even in acute care dealt with this, family that sees the resident only once a year mad because Grandma has gone downhill and they didn’t realize it. It must be the nursing homes fault, but generally the change is slow and the family is not aware of it because they never visit. In their eyes Grandma was still the lady who remembered everyone’s birthday, not someone who couldn’t remember what day it is and needs to be fed.

9. For what it’s worth, just spoke to one of the frontline ER doctors who is handling Covid 19 cases every day and he stated flatly that there will be no vaccine, no matter what anyone says, because this mutates too quickly. He also said we have to get back to some semblance of normality but use common sense.

I’m no expert, have no medical background but have known this guy for years. He’s highly respected in the medical community.

1. If he’s a frontline doctor, he doesn’t have any experience with measuring virus mutation rates either. (That’s a research scientist job, not a medical professional job).

That said, RNA viruses do have pretty rapid mutation rates. But coronaviruses have a “proof-reading” step which slows down the mutation rate some. Whether or not that’s ‘too quickly’ depends on how rapidly mutation leads to functional changes which interferes with immune system handling of the virus.

On the other hand, we’ve never made a vaccine for any coronavirus before. I’m guessing mutation rate isn’t the only issue here. He’s probably right there will never be a vaccine.

If it is because of mutation rate, ‘flattening the curve’ is a bad strategy – because that also means there will be no longterm immunity from infection either.

1. Fauci stated in 2004 they had successfully made a human tested vaccine for the first coronavirus – and they added it to the national stockpile. No one can answer me why they haven’t at least tried that vaccine.

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3335060/pdf/pone.0035421.pdf

If the vaccine gives you a major problem you didn’t have to begin with…

10. But without a vaccine you get the herd immunity by a lot of people getting sick and dying.

Almost… Herd immunity refers only to development of a population’s resistance to infection by the production of antibodies in the infected portion of that population. It it 100% possible to develop herd immunity to a completely non-lethal pathogen.

1. It it 100% possible to develop herd immunity to a completely non-lethal pathogen.

It’s also possible to have developed herd immunity to a lethal pathogen and continue to suffer fatalities from the pathogen both stably and unstably. As long as 1-1/R[0], the math doesn’t exactly care how many people die.

11. “But without a vaccine you get the herd immunity by a lot of people getting sick and dying.”

The dead do nothing for herd immunity. They are dead. Only the living have, or have need of immunity.

1. And 99.5 percent survive.

3. Or contrailians

1. I don’t mean to sound racist but, those people are fucking stupid and deserve every last thing that’s coming to them.

1. Actually they have mostly good things coming to them. See, when you do well enough for yourself you can afford a lot of unproductive or counterproductive ideas.

4. Anti-vaxxers should be all on board with herd immunity. If 50 percent of the population gets vaccinated, those with medical or religious concerns don’t need to.

5. “ The goal of social distancing practices is to stem the epidemic by driving the R0 of the coronavirus below 1.”

See this is the problem. We can’t agree on the goals. The goal isn’t to stem the epidemic. The goal is to not overload the ICU between now and the time we 1) develop better therapy, 2) develop a vaccine and/or 3) achieve herd immunity.

The goal is NOT to lock down the economy until the virus burns out.

Well at least that WASNT the goal, but recent behavior suggests that some people have moved the goalposts.

1. Very true. It’s highly probable that 50% of the population will catch this virus within the next two years. That’s because we don’t have herd immunity and don’t have a vaccine. And it’s probably eighteen months off before we get a vaccine. So we’re trying to keep the hospitals from being overwhelmed.

And we succeeded at that. Too well, we actually created problems for the non-ICU/non-COVID areas of the medical system. We were a little too strict. But the solution to too strict is NOT a free-for-all orgy of group hugs and sharing of toothbrushes, which seems to be the contrarian solution.

Both sides are being idiots. The Left wants us locked up forever with authoritarian governors micromanaging our lives, while the Right denies that there’s even a problem and wants to hold infection parties like it’s the chicken pox or something.

1. Then I’m with the “Right”. I think the equivalent of chicken pox parties will get those most vulnerable to a severe infection thru the period they need to be isolated the fastest, without overwhelming the ICUs. Obviously those people should not participate in the coronavirus parties, but we should definitely reopen the schools, camps, and day cares, and let the kids spread it around quickly.

2. Oh that they have. Apparently we all need to quarantine for 2 years now just so no one else dies. Ridiculous.

1. No one outside of your imagination is saying that.

1. LOL
“while the Right denies that there’s even a problem and wants to hold infection parties like it’s the chicken pox or something.”
You really aren’t intelligent.

2. They are heavily implying it by claiming you need a vaccine before lockdowns end, and that a vaccine would take 18-24 months to develop.

3. B: You are entirely right – the goal was to flatten the curve so that the health care system would not get overwhelmed. The goal was not and should never be to keep everybody locked down until a “cure” is found.

1. But we need universal testing before recognizing civil rights, right Ronnie?

4. You have a goal that involves lots of sickness and death, but doesn’t overload the ICU.

There are better goals: drive the virus incidence down to a very low level, then use contact and trace to keep it from killing many people at all.

South Korea, Taiwan, Australia and New Zealand are doing this successfully, suggesting that filling the ICU’s but not to capacity is not the way to go.

Oh, and that strategy opens things up pretty well, pretty soon, whereas the flat curve leaves a high percentage of people staying locked down of their own accord, with bad consequences for the economy and health.

1. New Zealand is setting themselves up for a much worse epidemic when Round 2 hits, because they will have the lowest herd immunity of all.

2. You can contact trace back in January and February when there were dozens of cases. Now there are millions. Bad luck with contact tracing — I don’t want the government monitoring everyone.

5. Someone forgot to tell Gov. Baker in Massachusetts. His idea now seems to be some form of restriction until a vaccine or some other therapeutic thing is discovered.

Masks all summer? No thank you, that could cause as many problems as that fixes. Masks for the next year, two years? Plain old creepy and questionable effectiveness. I’m actually starting to wonder as the points regarding all the separation may make us more susceptible to illness. I’m not entirely sure, but I think it makes sense on several levels.

I know one woman who was clean for over two years. She admitted to me she started using crack as a result of this mess between isolation and lack of employment prospects. She was even more embarrassed to admit I paid for it. I’ve forgiven her, and am now trying to give her what support I can to keep from self-destruction.

Between physical separation, imploding the economy and the continued mongering of fear, I’m far more concerned about the aftermath of this damn virus than the virus.

6. ”The U.S. as a whole is not yet close to achieving even the speculatively low estimate of the herd immunity threshold.“

We would have if we weren’t told to hide out for months. Well the scared ones who follow the nutty left are hiding.

1. The US, as a whole, will never be above the low estimate of herd immunity so long as anyone dies of COVID ever, practically by definition.

You people keep taking these definitions as though they had fixed meanings and were honestly delivered by people who conflate isolation, quarantine, and nationwide lockdown.

1. Of course we will get herd immunity – there’s only so many old af people it can kill.

7. I think I’ve finally figured it out… Bailey is auditioning to become a Voxplainer.

1. “Voxplainer” — excellent.

8. I hope they cleaned those estimates carefully after pulling them out of their…

9. “The upshot: The U.S. as a whole is not yet close to achieving even the speculatively low estimate of the herd immunity threshold.”

Hint, we dont’ have to stay in lockdown until herd immunity is achieved… this is because we won’t achieve it until people start interacting with each other.

Another Hint, this isn’t the dreaded killer you truly hoped it was Bailey. We know this now, yet you keep hyping up this disease like it is the new Black Plague when it is closer to a bad flu. Just stop already. It is beyond silly at this point.

Protect those in nursing homes, like Florida and Sweden have done, and let the rest of take the risk.

https://www.theguardian.com/us-news/2020/may/11/nursing-homes-us-data-coronavirus

1. On the bright side… looksike even the Democrats in NY are finally interested in why their death rate is so high and want to look into their dear governor.

https://www.breitbart.com/politics/2020/05/15/andrew-cuomo-scrambles-to-change-nursing-home-virus-policies-as-democrats-call-for-independent-investigation/

1. Yep. The questions are starting to come out, and New Yorkers are NOT happy. Some took out a billboard saying Cuomo killed their mothers.

2. I thought I’d never see that happen.

2. In terms of intelligence,
Florida Man > Ron Bailey

1. Intelligence maybe, maybe not, but certainly bravery. Borrowing a phrase; I’d rather have a division of Florida men (or anti-Vaxxers or statists) in front of me than a division of Ron Bailey’s behind me.

3. Good strategy. Pneumonias have always been sweeping out nursing homes, and most of the time we don’t even find out what the infectious agent was. Of course it was something circulating thru the general population — probably including some coronaviruses — unnoticed. We never tried to control these agents, except for influenza, in the general population.

10. The Trump Administration’s delays and failures in testing have left America playing Blind Man’s Bluff with C-19. Adding to this government inflicted blinding, is the outstanding question of whether any meaningful immunity to C-19 is gained by it’s survivors. A number of cases of reinfection have been noted, even within the very short history of this ongoing pandemic. Any real immunity, much less herd immunity, is a question that will take years to answer.

1. Dumbass.

https://www.reuters.com/article/us-health-coronavirus-southkorea-explain-idUSKBN22J0HR

“The findings suggested that some people who survived COVID-19 could become reinfected with the virus that causes it, potentially complicating efforts to lift quarantine restrictions and to produce a vaccine.

But after weeks of research, they now say that such test results appear to be “false positives” caused by lingering – but likely not infectious – bits of the virus.”

1. Pathetic, Trumpy, Moron.

But I repeat myself.

‘No Evidence’ That COVID-19 Antibodies Protect From Potential Re-infection

https://time.com/5827450/who-coronavirus-antibodies-reinfection/

1. Oh. You’re still listening to the WHO. No wonder you’re a dumbass.

2. You seem to be a Doomer. The WHO has already retracted its warning about re-infection.

2. Coronavirus COVID-19 (SARS-CoV-2)
Paul G. Auwaerter, M.D.

Updated: May 13, 2020

Most but not all patients recovered from COVID-19 producing neutralizing antibodies, but yet uncertainty as to how durable, and whether T cell responses also likely important. Not yet clear what is required to prevent a second infection.

https://www.hopkinsguides.com/hopkins/view/Johns_Hopkins_ABX_Guide/540747/all/Coronavirus_COVID_19__SARS_CoV_2_#4.5

1. An article that doesnt refute money as it simply explains uncertainty.

2. That is true of any pathogen. Most people developed immunity after one bout of chicken pox (before the vaccine). I, however, had it twice. Even vaccines are not 100% effective. Actually most aren’t even close, being around 60% effective. And some like the flu are 40 or less percent effective. So it isn’t surprising that those who recovered are not 100% immune. If they were it would be the first time in history that we have ever achieved 100% immunity from a pathogen via infection.
Do you know why you have to get three hep B shots? The majority develop immunity after the first shot. But some percentage require subsequent exposure to develop immunity. And some never do develop immunity.
As for durability of immunity, it likely varies from person to person. But this also isn’t unusual. It is why you need booster shots for most vaccines. Over time your body loses some of it’s acquired immunity and a booster helps build it back up. If anything the short term immunity appears to be a better argument for getting everyone infected at once. By delaying the spread of the infection you are in essence putting those who survived it once at risk again as they lose their immunity, while also putting everyone without exposure at risk.

1. As for herd immunity, even with a short term acquired immunity, it can still be achieved. This is for two reasons. Some individuals have more robust immune systems and their acquired immunity will last longer, or be permenant. The second reason is that large exposure and development of even a short term immunity drastically reduces the number of susceptible hosts. If the number of susceptible hosts is small enough it reduces the prevelance of the pathogen and thus it’s ability to trigger outbreaks.

1. This is at the core of the referenced analysis and research by Gomes/Lewis. Non-homogenous susceptibility is not considered a possibility in even the most basic SEIR models. Some people just ARE NOT going to get this.

2. Actually most aren’t even close, being around 60% effective.

That wasn’t always the case. Used to be vaccine development was reserved for the best candidates, and aside from infectious diseases like flu (where it’s a matter of finding the right strain), they were very effective — but we had far fewer of them. Now we have more and more vaccines that average less and less effective. Partly that’s a result of making very, very safe vaccines from components or via other strategies that produce a product far from the agent they’re immunizing against.

1. We also focused on the most dangerous pathogens. The ones that caused the largest outbreaks, with the most disastrous outcomes.

1. Trumpies and Idiots, but I repeat myself, never tire of being publicly wrong and idiotic:

FLASHBACK: Ten Days Ago, White House Economic Team Projected Pandemic Deaths Would Fall to Zero by Today

Ten days ago, the White House’s Council of Economic Advisors released what seemed like a patently ridiculous prediction: that the country’s Covid-19 death toll would drop to zero by May 15.

Today, that asburd, completely baseless estimate was confirmed — as more than 1,000 more Americans have succumbed to complications from the virus as of Friday afternoon, raising the overall fatality number to nearly 87,000.

https://www.mediaite.com/news/flashback-ten-days-ago-white-house-economic-team-projected-pandemic-deaths-would-fall-to-zero-by-today/

1. We’ve long passed the point where Trump and Trumpies must be fully discounted on everything regarding this pandemic and, as a prophylactic on everything:

Trump’s Former Favorite Coronavirus Drug Gets Torpedoed in Two New Studies

https://www.mediaite.com/news/trumps-former-favorite-coronavirus-drug-gets-torpedoed-in-two-new-studies/

1. Anyone who uses the term Trumpies and resort to nothing but personal attacks rather than actual arguments obviously act more on emotion than logic. Thank you for proving this once again. You realize you have completely undermined all your arguments with this sophomoric actions. You didn’t counter any of my points (especially as I said nothing about Trump). You didn’t offer any facts to counter what I said (mainly because you can’t argue with the science), so instead you resort to puerile smears, appeals to emotions and completely irrelevant screeching. Where did I mention Trump? Where did I mention any drug? No, I mentioned why your understanding of herd immunity and quarantine was incomplete. I showed why, even if you are right about acquired immunity being only temporary, that quarantine is exactly the wrong approach to take.

2. Through the use of these juvenile tactics you have just demonstrated that you are the one we should dismiss out of hand. You offer no actual arguments just attacks. You are a great caricature of the new left, all emotion no facts.

1. “great caricature of the new left”

No, I think he/she/it is a 4K hi-def image of the new left. No exaggeration required.

11. The U.S. as a whole is not yet close to achieving even the speculatively low estimate of the herd immunity threshold.

Perhaps some of our “laboratories of democracy” could achieve it?

12. R0 is affected by numerous biological, sociobehavioral, and environmental factors that govern pathogen transmission and, therefore, is usually estimated with various types of complex mathematical models, which make R0 easily misrepresented, misinterpreted, and misapplied. R0 is not a biological constant for a pathogen, a rate over time, or a measure of disease severity, and R0 cannot be modified through vaccination campaigns. R0 is rarely measured directly, and modeled R0 values are dependent on model structures and assumptions. Some R0 values reported in the scientific literature are likely obsolete. R0 must be estimated, reported, and applied with great caution because this basic metric is far from simple.

So, if I take a herd that’s 20% immune and space them out such that the R[0] falls to the point that 1-1/R[0] falls below 20%, I’ve achieved herd immunity.

If I take a herd that’s 20% immune with hoof-washing prevalency at 30% and boost the hoof-washing prevalence to the point that it depresses 1-1/R[0] to < 20%, I've achieved herd immunity.

If I take a herd that's 20% immune in winter, when the R[0] is higher or in poor and sick neighborhoods, where the R[0] is higher, and move them to warmer climates and provide better general living conditions, I've achieved herd immunity.

If I take a herd that's 20% immune and murder my way above 1-1/R[0], I've achieved herd immunity.

If I take a herd that's 20% immune and simply allow the majority of infected individuals to die, I've achieved herd immunity.

If I do some combination of any/all of the above and then some others, I've achieved herd immunity.

Pretty much the only way to avoid herd immunity is to go extinct.

1. FFS, where’s OBL? We might as well lay out COVID healthcare bins and let immigrants into the country unchecked to get the right number of people in each bin for insurance purposes for all this readily transparent and rigorously executed but highly subjecting and vaguely estimated math matters.

2. The funny thing about this part of the article is that Bailey actually admits R0 modifies itself overtime. In fact we still dont know the R0 at any given point due to the high asymptomatic rate. We can guess, but that’s about it. R0 is also not a constant as it is dependent on population statistics, so as infected increased, possible transmission decreases.

Yet Ronnie uses R0 as a constant..

1. The other thing is that R[0] doesn’t necessarily correlate in any real way to lethality (hospitalizations, mortality, CFR, etc.).

We are no longer herd immune to smallpox or polio but it they kill fewer people than measles despite the fact that we are herd immune to measles. If there were an outbreak of polio or smallpox, we would quickly achieve herd immunity, but its almost certain that more people would still die of those diseases, even after achieving herd immunity than would die of measles despite being ‘herd immune’ to both diseases.

Herd immunity is an outdated modality based on several, especially at this point, false premises. The model is not reality, the observer effect is too great. There are no more ‘wild’ herds unaware of syphilis for government TOP MEN to dose up and see how they die. There are no more communities with doctors that are more than 1 days travel. The ‘herd’ mentality/modality only applies to actual cattle and lesser animals that can’t conceptualize medicine. Humans, especially in the post-information age, aren’t the medical model equivalent to a herd.

2. Well, R0 is a constant, but it’s the R at time zero. It modifies into R1, R2, R3, … Rn, for times 1,2,3…n.

So the equation really should be 1-(1/Rn).

13. >>Estimates range from 70 to 10 percent.

respectfully, this is useful stat?

1. D: The article explains how various researchers come up with their estimates. You can see which ones you find more plausible.

1. yeah if that’s the spread it seems i’m choosing by ideology not math

2. You could do a better job explaining the assumptions behind the 60-70% numbers. (I’m pretty sure they assume the population homogeneously mixes, because it’s easy to model. But it’s sort of like assuming a spherical cow; real human populations don’t homogeneously mix).

14. also the concept of everyone covering their faces and hiding under the bed for 2 months *and then* lining up to be injected with the same shit they cowered from is ludicrously tragic.

1. Especially considering that if the Texas sharpshooter decides to draw a line at 40 yrs. old and say everyone “in the herd” is below it, he’s already effectively achieved herd immunity.

1. i was really enjoying 95% of Dallas under their beds.

15. The comment turns out to have been a bit hasty: The report on the city’s infection rate that the ambassador seems to have been referencing had already been withdrawn without explanation four days earlier.

Has there been any update on that report at all? Stockholm (not Sweden overall) is almost certainly the location that is closest to herd immunity. I read this awhile ago too but even though the report was withdrawn because of some error, it has never afaik been reissued. I’ve even looked at some Swedish language sources thinking I might find better info there than some US rag. Which actually makes me think it wasn’t an error that can be fixed quickly – but one of these early antibody tests that just isn’t specific/sensitive enough to actually rely on for some meta-statement.

1. Last I heard, the field hospital they built there was likely never going to be opened.

1. Probably like the field hospitals built here, and the mercy ships sent to NY and LA. They were barely used, wholly unnecessary as it turned out. Perhaps better safe than sorry, but still, the doomers act like they would have preferred to see dead people being shoveled out of the overwhelmed tent hospitals just so they could justify all their petty tyrannies.

16. “But if formerly standoffish herd members start frequently hanging out together in, say, bars, restaurants, theaters and baseball games, the percent of the population needed to achieve herd immunity will of course rise.”

Hmmm, I would say then that isn’t herd immunity at all. Herd immunity, to me, exists when people can go about their business in pre-COVID fashion with only an extremely small likelihood of getting infected.

1. You can’t achieve herd immunity without exposure. Avoiding exposure is only effective if the pathogen is short lived and you can avoid exposure until it is no longer present or has mutated to a less pathogenic variety. In order to do the second you have to have enough infections to induce mutations and there has to be a some evolutionary benefit to not being pathogenic. It is likely most of or normal flora was at one time pathogenic.
The first route seems unlikely, as this virus has susceptible animal hosts. The second is generally a long term process. Even though viruses mutate and a high rate, it takes an extended amount of time for the mutated variety to become the dominant strain. The fewer infected, the longer the process takes.

1. Herd immunity means NO Communist dictatorship exporting wave after wave of Communivirus to the rest of the world. This is the third Red China pandemic in roughly a decade!

17. Vaccine or no vaccine. Herd immunity or no herd immunity. It makes absolutely no difference if we continue to deny reality, attempting to live by distributing phony fiat money that will buy nothing ’cause all commerce is shut down. Democrats are both stupid and evil!

18. “What’s the Herd Immunity Threshold for the COVID-19 Coronavirus?”

What’s the Overdose Limit on retarded Covid articles?

What was the question again?

1. Can the CDC tell snot from Shinola?

20. Translation: “the State Science Institute looters have no clue.” When the Soviet Socialist Union entered post-Chernobyl collapse, Yeltsin’s crew cut almost all funding to parasitical scientist-impersonators. Boss Trump would do well to learn from that example.

21. Thank Ron, some actual math around herd immunity. Government and agency funded epidemiologists seem intent on suppressing this info.
Herd immunity is a bit of a misnomer, as is is “resistance” to infection which is a pretty ambiguous term. Of course vaccination based immunity for a single-strand RNA virus will not be immunity at all. But the point is that people need to understand there will still be infections. This is not polio or smallpox. This type of viral infection cannot be eradicated. Although it could mutate to a much less virulent pathogen.
But more importantly, the general population has likely reached a level of herd immunity already. The Shenzen Transmissibility Covid Study published in April studied family members quarantined with infected relatives in close quaters for an extended period. Only 11% were infected, and they calculated an R0 number of 0.6. This is generally consistent with data from the Diamond Princess, where over 3000 people were essentially bathing in the virus for 3 weeks, but 18.7% were infected. Likely the general population of Shenzhen are healthier and more resistant than then general population of a cruise ship.
Models that assume everyone is equally susceptible are grossly misleading. What the data tells us it that a very small subset of the population is highly susceptible to both infection and mortality. In Canada, a full 75% of mortality has been residents of Long Term Care facilities. Cohorts under 60 without underlying conditions appear to have a mortality rate below 0.1%.
If the goal was actually to reduce mortality, a tiny fraction of the cost incurred through lockdowns could have been focused on protecting LTC facilities by daily screening of the employees prior to entry.
Who believes that reducing mortality was actually the goal?

1. Thank you for bringing up the ship… That was the only model we ever needed. The Navy ship cemented it even more.

I think the lack of susceptibility in some populations will eventually be traced to cross-immunity with other coronaviruses (common cold varieties) – and that many, many millions have been exposed one way or another by now (and have been since late last year).

22. This is indeed one of the most challenging times for the whole world. We are trying to do our bit, by creating social awareness and distributing COVID-19 t shirts, on our website – https://champu.in/

23. And as we suspected/knew for some time now, the numbers have been fudged all along to incite more panic.

CO has revised their death down significantly (down by about 25%), after one local coroner insisted that a man who had died of alcohol poisoning not be counted as a COVID death despite a positive test for the virus. He came out publicly and said that the state was going to count this as a COVID fatality, but he wanted the people in his county to know that COVID did not kill the man. Subsequently the state has now rethought the policy and recounted…

DENVER — Colorado’s fatalities related to COVID-19 will now be counted as two separate data points, said the Colorado Department of Public Health and Environment in a release Friday.

Up to this point, anyone who died while testing positive for COVID-19 was counted as a coronavirus-related death.

Now, state health officials will distinguish between people who died directly because of the virus and people who had COVID-19 at their time of death but died of other causes that may not be attributable to the virus.

The two categories are now reflected on the state’s coronavirus data dashboard. Going forward, the state will report “Deaths Due to COVID-19” and “Deaths Among COVID-19” as separate data points.

24. Can’t we at least call it population immunity? Libertarians aren’t part of a herd.

And this is another reason (besides the economic devastation) that the shutdowns should end ASAP — if there’s another wave of coronavirus lurking, we’d be much better off getting more people exposed to it in the summer, when immune systems are stronger.

25. I noticed an error right away: your own source on R0 says “Assuming a serial interval of 6–9 days, we calculated a median R0 value of 5.7 (95% CI 3.8–8.9). ”

Your source says 5.7 and you quote “2.2 and 2.7” (which was an earlier study in Wuhan).

We’re not even close to herd immunity, and the US seems desperate to ignore science in preference to magic thinking. Around the world, we’re seeing that governments that do their jobs and societies that demand governments do their jobs while cooperating with scientists are having the best results — while freedom-loving populist countries like Italy eventually lock everyone up at home. There is a lot to learn about the expansion of government power if we look around the world today, and what makes the pendulum swing erratically vs maintain sane and moderate balance.

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