Has "Herd Immunity" Ever Been Achieved Without A Vaccine?

[intrepidity]

Last edited Fri Sep 4, 2020, 05:18 PM - Edit history (2)

My understanding is that "herd immunity" is only achieved with the use of an effective vaccine.

Is that correct?

ETA: Doh, of course there has. I think I was confusing something, perhaps semantics.... nevermind.

ETA2: Now I know what I was thinking of. From James Hamblin, discussing whether "herd immunity strategy" was a thing.

"It is the concept used in vaccination policy, to calculate how and when vaccines need to be deployed in order to prevent outbreak of a disease."

[AkFemDem]

1. 1918 flu. Nt

[dawg]

9. No. We never reached herd immunity with that virus.

It mutated into a less lethal version of itself and continues to circulate among us to this very day, making people sick but ususally not killing them.

For what it's worth, flu viruses are more susceptible to mutation than corona viruses.

[genxlib]

14. I'm not sure that adds up

If the strain mutated it would happen in a single new host. That new strain would spread on it's own from that one new host.

But the original strain that infected every other person in the world at that time would still be spreading also. So something stopped it from spreading.?

[dawg]

23. The less deadly strain outcompetes the deadlier one since it has more opportunities to spread.

Sick people, who can nonetheless still go from place to place, spread the infection much more effectively than those who quickly die from the disease. And the two versions of the virus are similar enough that survivors of the mild version gain some degree of immunity from both.

Eventually, the mild version of the virus is much more prevalent, and the original version lacks sufficient vectors to spread and is effectively crowded out. That is one theory of how the 1918 pandemic eventually died out.

[Demsrule86]

15. That is not true...for whatever reason...the 1918 flu disappeared in less than five years.

In order to study it...corpses were dug up to try to find the virus...so there was no 'herd' immunity.

....'Also known as the Spanish flu, this pandemic spread to nearly every part of the world ... study done in 2002, this unusually virulent strain of influenza A, subtype ... during the pandemic, thereby failing to create herd immunity....'


https://www.clinicalcorrelations.org/2009/09/23/the-forgotten-influenza-of-1918-when-a-strong-immune-system-becomes-a-weakness/

[Dan]

2. Maybe the 'Black Plague'?

[PSPS]

11. Black Plague is not a virus and can be cured with antibiotics, which they didn't have back then.

[lagomorph777]

3. The conquistadors had some herd immunity to smallpox, and Indigenous Americans had it for

syphilis.

Unfortunately for both populations (especially the Indigenous population), the reverse was not true.

[Demsrule86]

16. No herd immunity was ever achieved with either of those illnesses.

[LAS14]

4. My neighbor was the head of an Aids group at the NIH and is preparing...

... an article suggesting that the end of the 1918 flu epidemic was because of herd immunity. In early 1919 it just suddenly disappeared, after a fall resurgence. He has documented that the counts of cases (too low for herd immunity) were based on something not reliable (I wish I could remember), probably self reporting, and that the actual number of cases was way higher.

BUT... who wants to reproduce the 1918 flu epidemic? MILLIONS died!

[gollygee]

5. Before there were vaccines so yeah it's happened. nt

[Baclava]

6. I don't even like the term "herd immunity", humans are not herd animals

Worked wonders for the Wildebeest though

The vaccine

In the early 1960s, a vaccine was developed that protected domestic cattle from the rinderpest virus.

The domestic cattle had been the reservoir (i.e. the long-term host) for the disease, so treating them meant that the wildebeest population was protected too, even though wild wildebeest were not directly given the vaccine.

The rise of the wildebeest

Shortly after the Serengeti was designated as a National Park and researchers estimated the populations of the large mammals in the park. In 1957, it was estimated that just under 100,000 wildebeest were living on the Serengeti.

By 1971, just 10 years after the introduction of the rinderpest vaccine, the population of wildebeest was estimated at over 770,000 animals! That’s a remarkable recovery for an animal that only has one offspring per female per year.

The population trend is stable, and their numbers are estimated to be around 1,500,000



http://thatslifesci.com/2018-10-15-How-cow-vaccines-helped-giraffes-DAlcott/

[Iliyah]

7. Black Death - Bubonic Plague; Leprosy . . ..

no vaccine, where millions upon millions died.

[PSPS]

10. Bubonic Plague and Leprosy are not viruses and can be cured with antibiotics

[PSPS]

8. In general, that has never happened

Polio, smallpox and measles are examples of immunization eradicating the virus. "Herd immunity" is another way of saying that the virus cannot find susceptible hosts to infect and, thus, dies off. There are two basic ways to starve a virus into oblivion by removing available and susceptible hosts to infect: immunization and quarantine. If the lock-down earlier this year had been properly done and long enough, the virus would have died out on its own. But that ship has sailed.

There is a third way to starve a virus into oblivion, though. But it's not the desirable way. It involves having well over half of the available and susceptible hosts just die. This way played a role in the 1918 pandemic's demise.

[ProfessorGAC]

12. How About The Common Cold?

Just musing, no hard facts, but...
Could what we now call the "common" cold been far more pernicious, and we developed sufficient immunity that it can be fought off in 10 days or so?
I just recall that colds were far more serious a few thousand years ago. But, it's been a very long time since it was considered life threatening.
Could that be because of herd immunity?
Just spitballing!

[sakabatou]

13. No.

Either the population density became too low, and the disease burned itself out, or we got a vaccine for the disease.

[Squinch]

17. How about for a virus whose immunity is short-lived? This thing isn't over till there's an

effective treatment. Because they've been looking for a cure for common cold Corona viruses for generations without any luck whatsoever.

But to answer your question, there have been a few sicknesses that did burn themselves out. I don't know if they are viruses or what, but the Plague of Justinian killed tens of millions and then never came back. I think the sweating sickness is also eradicated and there wasn't any vaccine for it.

[roamer65]

18. Eradication has only been achieved through vaccines.

Smallpox is the prime example.

[intrepidity]

20. Yeah, this was the sort of thing I was thinking of nt

[roamer65]

22. Wild Polio is near eradication.

The mass vaccination for polio in Africa is getting us closer.

Even then sometimes the vaccine variant of the virus mutates and infects people. Rare but the news report I saw reported it.

[ananda]

19. Herd immunity is never achieved with a virus.

Only with a bacteria.

[intrepidity]

21. Oh! Interesting twist

Is that because of how quickly viruses mutate?