How long until herd immunity?

[Chronos]

So far, all I’m seeing here in this thread is armchair spitballing. I can do that, too. I was hoping that there’d be some information available from actual professional epidemiologists on the question.

Dr. Stappenbeck is presumably such an expert, but he’s not answering the question I asked. Yes, the fact that Delta is so much more infectious is relevant, in that it means that you need a greater percentage of the population protected before you reach herd immunity. But it also means that a greater percentage will get the disease. You still eventually reach the herd immunity point with a high-infectivity strain.

[Do_Not_Taunt]

I think the problem you’re running into is that no one (and I mean no one on earth, not just no dopers) knows the GQ answer to your question. So the best we can do is discuss the contours of it.

[Tfletch1]

@Chronos

You still eventually reach the herd immunity point with a high-infectivity strain.

Not with waning immunity and new strains. I guess we’d have to define “immunity” at this point. If it’s immune from infection all together, we may not reach that ever. Herd protection from severe illness is definitely achievable with vaccination + infection. That’s what scientists are describing as normalcy. But that means that at least 85% of the population has been vaccinated or infected. Regular boosting may be required for the next few years.

[echoreply]

@Chronos

information available from actual professional epidemiologists on the question

How long until herd immunity? The academic group Global Biosecurity has a twitter thread in which they basically say “we need to do better.”

The explanation is that this is an epidemic disease, and it will continue to come in cycles as long as there continue to be people able to be infected. They use smallpox and measles as examples of epidemic patterns.

The only way to achieve disease elimination is by vaccination or non-pharmacological controls (filtration, ventilation, masks, etc.)

Being a twitter thread, I’m sure the explanation is very simplified, and I also do not have the expertise to critique their conclusions. They are an academic research group specializing in epidemic response, and are from a respected university, so they are certainly professional epidemiologists. I was hoping the thread would have links to a more in depth article, but it does not.

[Magiver]

@echoreply

The explanation is that this is an epidemic disease, and it will continue to come in cycles as long as there continue to be people able to be infected. They use smallpox and measles as examples of epidemic patterns.

Does the smallpox vaccines stop people from spreading smallpox? Or is it a slower transmitting virus?

I ask this because the covid vaccine isn’t stopping vaccinated people from getting and spreading it but does slow it down.

[elfkin477]

@Tfletch1

But that means that at least 85% of the population has been vaccinated or infected.

How can we possibly not have already reached this threshold between infections over the past 2 years and vaccination, though? It seems as though we have not, in fact, had a lot of undiagnosed cases as many scientists have long hypothesized we have, or the re-infection rate is much higher than theorized*, or it’s actually significantly more contagious than it’s thought to be.

*and/or faulty tests are still saying people have covid when they don’t, so they’re vulnerable to catching it “again” later.

[Tfletch1]

@elfkin477

How can we possibly not have already reached this threshold between infections over the past 2 years and vaccination, though? It seems as though we have not , in fact, had a lot of undiagnosed cases as many scientists have long hypothesized we have, or the re-infection rate is much higher than theorized*, or it’s actually significantly more contagious than it’s thought to be.

*and/or faulty tests are still saying people have covid when they don’t, so they’re vulnerable to catching it “again” later.

Actually, 85% was too low a number. I should have said that 85% have to be immune to reach some kind of herd immunity. Even if we didn’t have waning immunity, the vaccines were 80-90% effective at preventing infection at best. People with mild covid cases are more likely to be reinfected, especially young people. Plus, there’s going to be overlap between vaccinated and previously-infected. I think we are a long way off from that 85% immune target and with waning immunity, we’ll drift farther away with time.

That’s why I’m monitoring a few countries with both high vaccination rates and cumulative infections. Portugal will be interesting to watch. 87% of their people are vaccinated and about 11% of their population had confirmed infection (probably closer to 30%).

[Chronos]

@Tfletch1

Not with waning immunity and new strains. I guess we’d have to define “immunity” at this point. If it’s immune from infection all together, we may not reach that ever. Herd protection from severe illness is definitely achievable with vaccination + infection. That’s what scientists are describing as normalcy. But that means that at least 85% of the population has been vaccinated or infected. Regular boosting may be required for the next few years.

I know that we’ll never reach total eradication. That was never more than best-case-scenario wishful thinking. That’s why I asked about herd immunity, instead, a well-defined term whose definition I am already familiar with: The level of immunity at which, on average, each infected person infects less than one other person, at which point the incidence of the disease therefore begins to decrease.

[Tfletch1]

@Chronos

That’s why I asked about herd immunity, instead, a well-defined term whose definition I am already familiar with: The level of immunity at which, on average, each infected person infects less than one other person, at which point the incidence of the disease therefore begins to decrease.

As @Do_Not_Taunt said,

I think the problem you’re running into is that no one (and I mean no one on earth, not just no dopers) knows the GQ answer to your question. So the best we can do is discuss the contours of it.

[Sage_Rat]

@Chronos

I know that we’ll never reach total eradication. That was never more than best-case-scenario wishful thinking.

For smallpox, we started vaccinations around 1798 and we achieved full eradication in 1980 - roughly 200 years later.

The problem isn’t so much in hitting the eradication rate of immunity, it’s hitting the eradication rate globally and staying consistent for a real, real long time. Since Covid spreads also in a wide variety of animals, that may be an even harder ask.

And it may seem like there would be no will to push to eradicate the disease once it becomes endemic but, I think, one strongly overlooked aspect of the pandemic is to realize that we’ve achieved the long impossible and cured the common cold.

Within society, between flu vaccines and the coming coronavirus vaccines, having to lie in bed coughing and sweating is going to become something that is largely optional. Some people, who would prefer to be disease free, are going to keep up on their immunations and successfully go years and decades without ever getting sick.

It is very possible that their success will lead others to follow and, eventually, you’ll have pockets of land where it’s a great travesty for someone to lie in bed coughing for a few days, and it will be giant news that it happened.

At that point in time, the push for global vaccination for the flu and the common cold will swell and we’ll finish the job.

To be sure, we’ll finish off polio and Dracunculiasis first. But, eventually, decades or centuries from now, Covid will get kicked off the cliff.

In the meanwhile, I’d stay focused on deciding whether you want to be on the leading edge of immunations or mentally segregate Covid from the common cold and the flu. Those do both kill people and have certainly killed more than Covid has, over the millennia. They’re going to keep on trying to do the same.

[Chronos]

I think that when you’re looking at 200-year-timescales, advances in medical technology will be a lot more relevant than a linear progression of the technologies we have now. By that time, we might eradicate covid, not through vaccinations, but via the use of decomfarbulators or whatever.