Talk:Herd immunity

message: Do we have anything, or can we produce, on herd immunity issues around covid-19?   There's a clear demand for this (70k pageviews / day in the last week). Andy Dingley (talk) 11:43, 16 March 2020 (UTC)
replies: text: I added COVID-19 to the table of HITs. There may not be a good place to mention it in prose but that may be fine. The references I used were taken from the article for SARS-CoV-2. ComfyKem (talk) 23:20, 17 March 2020 (UTC)

text: I checked the references given on R0 and HITs for COVID-19. The references provide estimates of R0, I did not find anything on HITs. I doubt that HIT is known at this stage. Consider to delete the HIT estimates for COVID-19.— Preceding unsigned comment added by Behinddemlune (talk • contribs) 16:01, 18 April 2020 (UTC)
thread_title:  Covid-19 

message: Without immunisation I understand populations can become more resistant after multiple sweeps of a disease, so possibly with smallpox, mortality was high in previously exposed populations in Europe, but without that prior exposure First Peoples had catastrophic mortality. This was not herd immunity. That is, after repeated exposure morbidity and mortality in a population may reduce. Is there/should there be an article covering that. Paul foord (talk) Paul foord (talk) 09:43, 20 March 2020 (UTC)
replies: text: Yes, the phenomenon you describe is a form of herd immunity. Vaccination is not the only way to achieve herd immunity. Jaredroach (talk) 17:03, 26 February 2024 (UTC)
thread_title: Populations can become more resistant after multiple sweeps of a disease

message: A popular theory of a new virus which humanity wasn't exposed to before, but looking at 95% recovery/5% death rates, some people are harder or easier affected by Covid-19. Scientists check into genetics of Covid-19 patients (and high risk factors like age, immunity compromise and health conditions), along with blood types such as A, B, AB and O; and the RH factor to determine why some people are easily recovering and others are dying faster. One way to explain this phenomena is ancestrally, there were rare but probable Covid-type plagues in human prehistory or plagues of "unknown origin" described in global pandemic history. A new virus wouldn't kill a scant 5% of their infected rate population, then again a coronavirus similar to its relatives like the common cold, influenza, poxes (i.e. chickenpox, measles, rubella and the now extinct smallpox), herpes (STD) and canker sores can be recognized as "familiar" in some people's immune systems geared up to fight it. And oddly, SARS and MERS which are the worst type of coronaviruses keep originating in East Asia (then spread outward globally in an age of massive travel, but they tend to disappear like SARS or reappear like MERS). Is there evidence of many Chinese and East Asians were previously exposed to Covid-type disease than Europeans and caucasians who had higher death tolls? 2605:E000:100D:C571:7D82:A683:E434:DB3D (talk) 15:15, 30 April 2020 (UTC)
replies: text: No. There is no such evidence. Jaredroach (talk) 17:05, 26 February 2024 (UTC)
thread_title:  Genetics and blood types in disparities of Covid-19 deaths and recoveries 

message: In the section Mechanics, the paragraph that starts with "These calculations assume ..." alleges an assumption about the calculations in the preceding paragraphs – more specifically, that the entire population is susceptible. Is this a left-over from an older version? The calculations explicitly use a variable  S, representing the proportion of the population who are susceptible to infection. I do not see the difference between the effective reproduction number Re and . Any objections to removing this paragraph (with an appropriate adjustment to the next)? To make things cleaner, we should define the notion of "effective reproduction number" in the article Mathematical modelling of infectious disease and define it mathematically by .  --Lambiam 11:55, 2 May 2020 (UTC)
replies: text: I checked the sources used for that portion and this reference appears to define Re as you say. So some sentences seemed unneeded and I reworded a bit in the "Mechanics" section. Velayinosu (talk) 03:13, 16 May 2020 (UTC)
replies: text:  One assumes something as a hypothetical, whereas one presumes something to be the case. "Let us presume Timmy went to the bus stop at 8:00 a.m. as he does every weekday" vis-à-vis "Let us assume that Timmy was kidnapped". kencf0618 (talk) 02:36, 18 September 2020 (UTC)
thread_title:  "These calculations assume ..." what? 

message: I've included today's BBC report on the estimated HIT range, but it would be best to include the more recent scientific papers I think. kencf0618 (talk) 10:07, 29 June 2020 (UTC)
replies: text: I added a review article about this since that is more appropriate than a news article. Velayinosu (talk) 01:01, 30 June 2020 (UTC)
thread_title:  BBC R0/HIT 

message: More accurate R0 range is 2.5-4. I don't know where the HI threshold 50-83% have come from. Someone with expertise needs to weigh in and update maybe. - hako9 (talk) 22:59, 13 September 2020 (UTC)
replies: text: Could someone comment whether renaming the table in #Mechanics section with title changed to "Estimated R0 and HITs (herd immunity threshold assuming no pharmaceutical interventions) of well-known infectious diseases" would be appropriate or not, or is it just assumed that the lower and upper limits are a function of R0 only? - hako9 (talk) 01:34, 18 September 2020 (UTC)
replies: text: No idea. I only know that absent pharmaceutical intervention herd immunity takes a lot of dead cows. kencf0618 (talk) 02:37, 18 September 2020 (UTC)
thread_title:  R0 and HI threshold for Covid 

message: Without looking for it the following irrelevant but disturbing headline came up in a search result.
It seemed to be fake news as the WHO cannot be so brazen in promoting vaccines that they will mess around with our language.
I wonder if they have tried to adjust reality in the other languages they may publish opinion in.
WHO (secretly) changed their definition of “Herd Immunity” Global health body dishonestly alters meaning, claims you need a vaccine to achieve it
If they have adjusted the robots.txt file to clear archive.org scans of their site after this (or some other propaganda act) then they need to be censured.  Preventing archive.org from crawling a global health site is not right.  What if the servers are blown up and the only copy is at archive.org, only it isn't, this is not a good sign.
Is there a place on this wiki page that we can add the proposed new meaning that the WHO gives to Herd Immunity so that people know what to expect when they decide to embark on a career of helping people against the best wishes of the largest ally they though they had.
Idyllic press (talk) 20:19, 4 January 2021 (UTC)
thread_title:  Is this possible, an error, deliberate, what is up with the WHO? 

message: Because of the Great Barrington Declaration and other similar stuff, we have several links to this article that are less than helpful. Just one example:
*The Richie Allen Show says, "In 2020, Martin Kulldorff of Harvard Medical School appeared on the programme to oppose the COVID-19 lockdown. As a co-author of the Great Barrington Declaration, he favoured an approach based on herd immunity to the disease."
Of course, the article does not mention what that approach is. After all, the GBD method is not the only "approach based on herd immunity", and the GBD just tried to appropriate the term for their method, which is not relevant here. I think we should have a better way of handling such links, one which does not let them do that. But I don't know how. Maybe change the redirect Herd immunity approach to Great Barrington Declaration and always use it instead of a link here? --Hob Gadling (talk) 13:23, 8 January 2021 (UTC)
thread_title:  "Herd immunity approach" 

message: Should population heterogeneity be included in the article?
HIT = 1 - (1/R0)^1\lambda
https://judithcurry.com/2021/01/10/covid-19-why-did-a-second-wave-occur-even-in-regions-hit-hard-by-the-first-wave/#more-26868
https://science.sciencemag.org/content/369/6505/846
--Rcsmit (talk) 12:50, 14 February 2021 (UTC)
thread_title:  population heterogeneity 

message: Referring to this sentence near the start of the article: "Tetanus, for example, is infectious but not contagious, so herd immunity does not apply." - the difference between "infectious" and "contagious" needs to be explained here, as it is not clear or self-evident - I suspect most non-medical people probably regard the two words as interchangeable.  Neither the articles "Contagious disease" nor "Infection" seem to clearly explain the difference. M.J.E. (talk) 13:20, 28 May 2021 (UTC)
replies: text: Correct. Most instances of this concept should be written as "contagious", particularly for this article. Jaredroach (talk) 17:18, 26 February 2024 (UTC)
thread_title:  Difference between "infectious" and "contagious". 

message: The HIT is a value calc. only by the given value of R0. It does not cover any other relevant aspect (like decay of immuno-response with time, an efficiency of immuno-response lower than 100% etc, mutation). In the case of Covid - Omicron variant, the deduced number seems to indicate that herd immunity is feasible - against the scientific result that herd immunity is not achievable to the current knowledge, as not-covered aspects lifts the threshold beyond 100%. As the HIT number is uncritically calculated - I would suggest to remove the specific column from the table as it is misleading (Note: I was looking for this specific case - and was surprised to find such an unlikely number - till I realized that that is a number generated by a WP-User. To be clear, Ro is a measured (averaged) value - HIT in this table is not a value from a source but self generated) and therefore, actually, violates WP - Rules --DAsia (talk) 01:00, 16 June 2022 (UTC)
thread_title:  herd immunity thresholds (HITs) - To be removed from Table ? 

message: I think it may be good to add very brief info about this. Maybe one would need to wait for a scientific review or e.g. the CDC to comment on this for a sufficiently reliable source. But for example, maybe such a source already exist, or it could be made clear that this is only what has been suggested (based on their reported results) there and that a better source is still needed.
It's included in 2022 in science like so:
A preprint suggests that SARS-CoV-2 antibodies in or transmitted through the air are an unrecognized mechanism by which, transferred, passive immune protection occurs.
It's relevant and important to know that protection from passive (herd) immunity is thought to wane over the course of weeks to months, including for such cases, if it's not sustained but I think this is already included elsewhere in the article.
Moreover, this may also be relevant (note that this not necessarily about airborne aerosol transmission):
Antibodies from vaccination can be present in saliva and thereby may have utility in preventing infection.
And things like / including this may also be relevant and aren't mentioned in the article:
* Bovine (corona)virus-immune milk
Prototyperspective (talk) 12:11, 1 July 2022 (UTC)
thread_title:  Please update with: info on potential aerosol & saliva transmission of antibodies 

message: The graphic entitled, "Herd immunity protects vulnerable communities" is confusing and raises many questions, IMHO. It's also redundant with the first graphic, which explains the various possible scenarios, including herd immunity (the third scenario) and explains it better, but doesn't call it out as "herd immunity." (If that is wrong or you want a list of the questions and issues w/ second graphic, please advise and I will post.) Can we just delete the second graphic, and add the term "herd immunity" to the third scenario in the first graphic? 2603:8000:8F40:3B08:11EF:6BF7:659C:893F (talk) 19:30, 1 May 2023 (UTC)
replies: text: I like both graphics. One is quick and easy to understand, the other offers dense information. There is distinct information in both graphics. Jaredroach (talk) 17:13, 26 February 2024 (UTC)
thread_title:  Graphics