Delta Impact on Herd Immunity
 

Delta just dramatically pushed the herd immunity threshold higher.

And immunized individuals can still be carriers.

COVID-19 herd immunity? It’s not going to happen, so what next?

August 3, 2021 5.55am EDT
Shabir A. Madhi,

COVID-19 herd immunity? It's not going to happen, so what next?

The best hope of beating the pandemic is to vaccinate as many people as soon as possible.

Any notion that COVID-19 was going to last for just a few months was very much misplaced in 2020. Especially after it was recognised that the SARS-CoV-2 virus was largely spread through the airborne route, all indications were that it would cause repeat bouts of waves. This is what happened in the flu epidemic of 1918.

Herd immunity isn’t achievable. We need to learn to live with COVID-19

In addition very few scientists predicted that we would see the type of mutations that occurred over such a short period of time. This has resulted in the virus becoming both more transmissible and more able to evade immune responses.

The evolution of the virus has been so rapid that the Delta variant, which is currently dominating the world, is at least twice as transmissible as the ancestral virus that was circulating.

What this means is that herd immunity is no longer a discussion the world should be having. We should start to avoid using that term in the context of SARS-CoV-2, because it’s not going to materialise – or is unlikely to materialise – during our lifetimes.

When politicians and others speak about herd immunity, unfortunately, they are under the misconception that the current tools we’ve got are adequate to eliminate the virus. It’s not what we have at hand right now.

Instead we should be talking about how to live with the virus. The tremendous success that’s materialised with COVID-19 vaccines allows us to do this, without actually getting into the herd immunity threshold.

Peddling the concept of herd immunity creates a misconception that we are actually going to get to a stage where this virus is going to be eliminated. That’s unlikely to happen. It will continue circulating.

There are a number of dangers in continuing to make people believe it’s possible.

Firstly, it could dent confidence in vaccines. Even if South Africa gets to its target of 67% of the population being vaccinated – as set out by the Department of Health – there will still be outbreaks of COVID-19. The result will be that people begin to doubt the benefits of being vaccinated. Also, for the now dominant Delta variant, immunity against infection (not only COVID-19 illness) would need to be closer to 84% for the “herd immunity” threshold to be reached.

Secondly, failing to face up to the reality that herd immunity can’t be achieved will mean that countries like South Africa will continue to believe that ongoing restrictions will get them there. That will compromise the lives of people on multiple fronts – including education and livelihoods.

What is herd immunity?

Herd immunity is when someone infected by the virus won’t, on average, infect another person. So you reach a state where the immunity in the population against infection by the virus is such that there are too few people in the environment for sustained onward transmission to take place to others.

This is because they’ve developed immunity against being infected, or at least have developed immunity to the extent where even if they were infected, they would be able to clear the virus very quickly and wouldn’t be able to transmit it to other people.

So herd immunity essentially means that you have brought about an absolute interruption in the chain of transmission of the virus in the population in the absence of other interventions that too could interrupt virus transmission such as wearing of face masks.

But some changes have forced a shift in our thinking about herd immunity. It’s now viewed much more as an aspiration rather than actual goal.

What’s changed

Firstly, the evolution of the virus and the mutations that have occurred.

One set of mutations made the virus much more transmissible or infectious. The Delta variant is just such an example. Initially we thought the SARS-CoV-2 reproductive rate was between 2.5 and 4. In other words, in a fully susceptible population every one person infected would on average infect about two and a half to four other people. But the Delta variant is at least twofold more transmissible. That means that the reproductive rate of the Delta variant is probably closer to six rather than three.

The second change is that the virus has shown an ability to have mutations that make it resistant to antibody neutralising activity induced by past infection from the original virus, as well as antibody responses induced by most of the current COVID-19 vaccines.

The third big issue centres on the durability of protection. Our memory responses are lasting for at least six to nine months at the moment. But that doesn’t mean that they will protect us against infection from variants that are evolving, even if such memory responses do assist in attenuating the clinical course of the infection leading to less severe COVID-19.

The fourth issue conspiring against us being able to reach a herd immunity threshold any time soon is the inequitable distribution of vaccine across the world, the slow uptake and the sluggish rollout. Unfortunately, this provides fertile ground for ongoing evolution of the virus.

No country is going to lock its borders perpetually. This means the entire global population needs to reach the same sort of threshold round about the same time. At the moment just 1% of the populations of low-income countries have been vaccinated. And 27% of the global population.

With the Delta variant, we would need to get close to 84% of the global population developing protection against infection (in the absence of non-pharmacological interventions) in as brief a period of time as possible.

Next steps

The only sustainable solution is to learn to live with the virus.

This will require ensuring that we get the majority of individuals, especially adults, and particularly those at a higher risk of developing severe COVID-19 and dying, vaccinated as quickly as possible. In my view this could be achieved in South Africa with 20 million people vaccinated – not the 40 million target set by the government. But the 20 million would need to include 90% of people above the age of 60, and 90% of people above the age of 35 who have co-morbidities.

If South Africa achieved this milestone, it could get back to a relatively normal lifestyle even with the virus continuing to circulate and causing the occasional outbreak. It would also ensure a threshold that guaranteed its healthcare systems weren’t going to be overwhelmed, and that people were not going to die in large numbers.

We are simply going to have to become comfortable with the idea that SARS-CoV-2 is going to be like one of the numerous other viruses that circulate that cause respiratory illness each day. Usually mild infections, and less often a severe disease.

So people will, unfortunately, continue dying of COVID-19, but certainly not at the magnitude that’s been seen over the past 18 months. A major advance would be for COVID-19 to be no more severe than what is seen every influenza season (10,000 to 11,000 deaths) in South Africa.

The UK experience is where we should be heading. That is getting back to a relatively normal lifestyle, provided that we’ve got a adequate number of people vaccinated, and particularly people who are at higher risk of developing severe COVID-19.

The UK is currently close to 85% of adults that have already received at least a single dose of the vaccine. As a result they’re able to remove almost all restrictions.

The UK is seeing an increase in number of cases of the Delta variant. But they’ve seen very nominal changes when it comes to hospitalisation and death. The vast majority of people (97%) who still end up being hospitalised and dying of COVID-19 in the UK are those who decided not to be vaccinated

Your post seems reasonable and I agree. I said to my husband that I never thought that we would see such a time, EVER.

What next?

A bunch of people die, everyone else either gets the virus or doesn't. It mutates some more, a bunch of people get sick with a variety of symptoms, some worse than others. Maybe a few people get stuck on ventilators for the rest of their lives, a couple have to get a lung removed.

Meanwhile, everyone else just carries on and lives their lives. Except without their daughter, who's dead from the virus. And without money since it's all sunk into 24/7 nursing care to keep their 40-year-old dad alive. And without their son, who came down with really bad symptoms but didn't take any precautions, and spread it to his best friend, who died of the disease. Sonny committed suicide because he couldn't live with the guilt.

Maybe some families were left intact, no losses, huzzah! But their neighbors have stopped being neighborly, their cousins are now avoiding close contact because THEY have lost friends and neighbors...a few schools have had to make adjustments because some teachers are now dead, so your kids are being educated by a new batch of teachers who have no prior experience...

You have a new mailman now, and he doesn't know that you need the mail put through the doggie door instead of the mail box over the doorbell, because some whacko down the street steals the circulars for coupons...

That's what's next. That is the new world coming. Just a few more dead people. No big deal right?

Unfortunately since social media became popular because of the World Wide Web (internet) and 24 hour cable became what many watch, much false information regarding just about any subject you can name has emerged. Real investigated facts and real news has almost become a thing of the past. People are gullible and you find them following charismatic media personalities who spin information to feed their own pocketbooks with thousands/millions of dollars. Conspiracy theories are the state of the art with a new one every few days. For example, as science finds more about the coronavirus and makes changes to react to the new findings, we are told that we were lied to and not to listen to the science who got it all wrong in the first place. Selfish politicians (of both parties) haven’t helped the situation either. Instead of what can I do for my country it’s what can I do for me. That said, I am confident that in the long run science will prevail and we will get back to business as usual in this great country we call the United States of America.

And meteoroids will strike the earth and the oxygen levels will dwindle. The plants will die and aliens will take over the planet…

I hope you don't mind, I am stealing your post and spreading it. SO many focus on now and me, and ignore the ripples of their actions.

It might, and NASA and others are taking steps to prevent that. But at this point, we don't really have a working solution.

However, we DO have a working solution for COVID. Well, we did until so many refused to use it, and now we have a new mutant and so, we may be back - for a while - to not having a solution to that either.

Here's a crazy idea - why don't we focus on doing what we can, and not worry about what we can't.

So maybe we shouldn't obsess about variants because there's bound to be a lot more. Just offer a booster shot every year for the original COVID which does offer some protection against the variants. If indeed a booster is even need as they need to find out the level and strength of antibodies of those vaccinated. The clinical trials were last summer so they must be testing those individuals or you'd hope so. I haven't heard any reports yet on their findings.

But according to the CDC, those who have had Covid are much less likely to be reinfected. So if the Delta strain is much more contagious and less deadly, we will actually reach herd immunity quicker…

Great idea, there is NO way a variant could occur that we can't provide a booster for.

How about we try to prevent the spread to prevent the variant. That we KNOW how to do, NOW. As opposed to hoping we can come up with something maybe later.

Let’s look at the absurd scenario where every single American was vaccinated. The Delta variant didn’t originate here. With our open boarders, we would still be facing a variant that wasn’t prevented by the vaccines. So, since it appears that natural immunity is more effective than vaccines, just vaccinating those at risk, makes the most sense.

All the King's horses and all the King's men, couldn't put Humpty Dumpty together again.

Sometimes there is deep wisdom in nursery rhymes that are very old.

Sometimes there is NO answer to huge problems.

You CAN lead a horse to water but you can't make him drink.

Not everyone is given at birth all the same abilities to perceive and understand.

We are all created valuable, (at least in MY philosophy) but we are not all created equal.

And again, Sometimes no matter how much thinkers think, and the worlds thinkers are all focused on this problem, and just like Climate Change/Global Warming, there is nothing at this time that can immediately and effectively make things better. If there were, it would be happening.

Come back in about two years, and you will have a definite answer to all your questions.
In the meantime, carry on regardless.

Leave the unvaccinated alone. It should take care of itself.

People just became more gullible and believe what they feel convenient with. It’s quite sad the older on gets they are more set in their beliefs even if they might be proven wrong facts mean nothing.

The shots don't help prevent the spread, if the majority of the population refuse to get them. But our tax dollars, and health insurance premiums, DO pay for those who refuse to get the shots and end up sick and unable to pay the bill.

You may not steal it! But you may use it!

The war has changed...

https://context-cdn.washingtonpost.c...f75165.#page=1

Summary
▪ Delta is different from previous strains – Highly contagious
– Likely more severe
– Breakthrough infections may be as transmissible as unvaccinated cases
▪ Vaccines prevent >90% of severe disease, but may be less effective at preventing
infection or transmission
– Therefore, more breakthrough and more community spread despite
vaccination
▪ NPIs are essential to prevent continued spread with current vaccine coverage

IMO Only thing that’s going to stop this virus is when the virus plays itself out. It never should of made the jump to humans. Humans caused this.

Our health tax dollars also pay for those who overeat and don’t exercise. They pay for those who smoke. Did you know that smoking accounts for roughly 480,000 deaths per year - every year…

Well, the "majority" of the population HAS been vaccinated (not including children, for which the vaccine has not yet been approved), so there's that...

As of 08/02/2021 - 58.4% have received at least 1 shot, 50.2 have received both shots...

Disagree and agree.

Disagree. This virus will never play itself out. It's going to act like the flu and the common cold. Different strains will evolve making vaccines and natural immunities less than 100% effective. I think the current concern about the deadliness is way overrated but the good news is the mutations will become less deadly over time.

Agree. Humans did cause this. Chinese humans. I still don't understand why our country as a whole is not in agreement and totally pi**ed off at the CCP. You can point to Trump, Fauci, conservative media, liberal media, blue states, red states, pro maskers, anti maskers or whatever. The fact of the matter is, the CCP allowed dangerous gain of function research in a substandard lab that led to the virus escaping. THAT is where the blame lies. It's time we stop pointing fingers at each other and collectively start going after the true culprit.

Segregation of vaccinated and non-vaccinated may be forthcoming.

Who cares where it came from. It is here now so as one smart man "Grumpy"just said we have the tools now. Get vaccinated. Real simple

Yep. I agree its right on point but Im sure some naysayers will pipe in

We have a solution for covid but it has been kept from us...HCQ & Ivermectin. Many doctors attest to this. Look us Front Line Doctors, Natural News and so much more if you would just look.

“And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.” – Revelation 13:17

“Vaccination is a barbarous practice and one of the most fatal of all the delusions current in our time. Conscientious objectors to vaccination should stand alone, if need be, against a whole world, in defense of their conviction.” – Mahatma Gandhi

Originally I would have thought it was an accidental release of a virus, now with the variety is happening Delta v and lambda I tend to think it was a military research lab but again that's only my opinion. Às a science fiction reader, I certainly now believe that we're going to have masks for the rest of our lives as this is going to become much more of a situation than just a common cold coming out of China every year and I think this will be one more nail in the coffin of expenses that the US budget has to incur. On a positive note I am pretty sure that we have excellent pharmacological research companies in the US and elsewhere

Just to cheer you up, take note of the Lambda variant, for which the vaccine seems not to work or not to work as well. I read yesterday in Newsweek online that it’s the dominant form in Peru, and there are about a thousand cases in the US so far. Don’t throw away those masks and gloves or that hand sanitizer. What if new variants keep popping up and shutting us down for the next century? What if a new variant also has a much higher death rate?

Ons vir jou suid afrika
South Africa has unique challenges superstition is a big big factor 70% of people missed their vaccine appointments in South Africa alone it will be a long long haul to get to herd immunity

The first is cherry picking out of the bible--and not very relevant to the current situation--to suit one's own belief.


The second is a faith-based opinion that has nothing to do with science, from one of the original anti-vaxxers, talking about small pox vaccination. A hundred--hundred!-- years ago. Opinions and faith-based ideas that differ from what's empirically established is not valid science.

This post would be absolutely correct, IF you just substitute the word "quacks" for "doctors"

I accept the premise of your post which is why I simply do not understand our government's lack of interest in therapeutics? Many doctors have written that they have had considerable success with new and existing drugs in the treatment of COVID, yet I have also read that hospitals routinely are not using them. Why? I know some people are down on any kind of treatment because an unnamed former president suggested some, but that is not an intelligent way to make decisions.

If we accept that this virus is going to be around from a long time to forever, let's embrace finding effective ways of treating it.

Thank you so much for your post. I couldn’t agree more.

Florida: 95% of hospitalizations -Unvaccinated.
100 deaths: almost all -unvaccinated.
Vaccines: not 100% but upwards of 90% effective in preventing infection and offer protection in the event of infection.

Which post... Who is being thanked?

Just Get Vaccinated
 

The case rate among fully vaccinated is very, very low.

COVID-19 Vaccine Breakthrough Cases: Data from the States | KFF

To quote from the above link:

Overall, we find that:

Half of states (25) report some data on COVID-19 breakthrough events (see Table 1). Twenty-four provide data on breakthrough cases, 19 on hospitalizations and on deaths.
Fifteen of these states regularly update these data, often on a weekly basis. The rest use a different frequency, have one-time reports, have stopped updating, or have an unclear reporting frequency.
The data reported from these states indicate that breakthrough cases, hospitalizations, and deaths are extremely rare events among those who are fully vaccinated against COVID-19 (see Figure 1). The rate of breakthrough cases reported among those fully vaccinated is well below 1% in all reporting states, ranging from 0.01% in Connecticut to 0.29% in Alaska.
The hospitalization rate among fully vaccinated people with COVID-19 ranged from effectively zero (0.00%) in California, Delaware, D.C., Indiana, New Jersey, New Mexico, Vermont, and Virginia to 0.06% in Arkansas. (Note: Hospitalization may or may not have been due to COVID-19.)
The rates of death among fully vaccinated people with COVID-19 were even lower, effectively zero (0.00%) in all but two reporting states, Arkansas and Michigan where they were 0.01%. (Note: Deaths may or may not have been due to COVID-19.)

The surge in COVID is occurring among the unvaccinated.

The solution to COVID, and getting back to life as “normal” is: Get vaccinated.